Cardiorespiratory Fitness and Pulmonary Function in Parkinson’s Disease: A Cross- Sectional Study with Clinical Correlations

Cardiorespiratory Fitness and Pulmonary Function in Parkinson’s Disease: A Cross- Sectional Study with Clinical Correlations | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Cardiorespiratory Fitness and Pulmonary Function in Parkinson’s Disease: A Cross- Sectional Study with Clinical Correlations Yu-Zhen Chen, Qin Zhao, Dan-Mei Lan, Shuang-Fang Li, Yue Li, Lu Wei, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7255514/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Parkinson’s disease (PD) is frequently accompanied by impairments in cardiorespiratory fitness (CRF) and pulmonary function (PF), which may diminish quality of life and limit functional independence. This study aimed to assess CRF and PF in patients with PD and explore their interrelationship. Methods This cross-sectional study enrolled 48 patients with PD (Hoehn-Yahr stage 1–4) and 17 age-matched healthy controls. All participants underwent comprehensive assessments, including pulmonary function testing (PFT) and cardiopulmonary exercise testing(CPET), alongside the systematic collection of demographic and clinical characteristics. PD patients were additionally evaluated for motor symptoms using the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III), disease severity (Hoehn-Yahr stage, H-Y stage), cognitive function (Montreal Cognitive Assessment, MoCA), and activities of daily living (Modified Barthel Index, MBI). Correlation analyses were conducted to investigate the relationship between PFT and CPET outcomes, with a focus on identifying potential associations between respiratory impairment and exercise capacity in PD. Results Compared to controls, PD patients demonstrated significantly reduced PF and markedly impaired exercise capacity. Although 84% of PD patients showed preserved PF, 96% exhibited severe reductions in CRF. Strong correlations were observed between pulmonary measures and exercise capacity. Higher CRF levels were associated with better cognitive function and greater independence in daily activities. Disease severity was inversely related to CRF. Conclusions PD patients experience significant declines in both PF and CRF, which are linked to worse clinical and functional outcomes. The discordance between preserved PF and severely reduced CRF suggests that non-pulmonary mechanisms may contribute to exercise intolerance. CPET should be integrated into PD assessments to guide personalized rehabilitation strategies. Trial registration: Not applicable. Parkinson’s disease Cardiorespiratory fitness Cardiopulmonary exercise testing Pulmonary function Pulmonary function testing Figures Figure 1 Introduction Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor dysfunction, though its non-motor manifestations are equally debilitating. Among these, declining cardiorespiratory fitness(CRF)has emerged as a critical yet understudied feature in PD patients[1]. Research indicates that individuals with PD exhibit a 20–30% reduction in peak oxygen uptake (VO₂peak) compared to healthy controls[2], with diminished CRF closely linked to poorer quality of life, cognitive decline, and disease progression[3, 4].Encouragingly, structured aerobic exercise interventions have demonstrated efficacy in enhancing cardiopulmonary function, cognitive performance, and mood regulation in PD patients, potentially slowing disease advancement[5, 6]. Consequently, evidence-based, personalized exercise prescriptions are increasingly recognized as a cornerstone of PD rehabilitation. Cardiopulmonary exercise testing (CPET), the gold standard for assessing CRF, provides critical data to guide individualized exercise regimens[7]. However, implementing CPET in PD populations remains challenging due to motor impairments and autonomic dysfunction[8]. As a result, existing studies predominantly focus on early-stage PD, leaving cardiopulmonary adaptations in moderate-to-advanced disease poorly characterized. Although there is considerable research on pulmonary function (PF) in PD, the interconnectedness of cardiorespiratory function is often overlooked[9]. Most studies focus on isolated assessments of respiratory or exercise-related symptoms with limited exploration of the dynamic relationship between the two[1, 10]. But understanding this relationship is crucial for early identification of high-risk patients and improving clinical outcomes. This study integrates pulmonary function testing (PFT) with CPET to systematically compare cardiopulmonary performance and healthy controls, aiming to provide a detailed profile of both respiratory and exercise limitations throughout the disease course and optimize rehabilitative strategies by delineating CRF decline patterns. Methods Study Participants This study was designed as a cross-sectional, retrospective research project conducted at the Shanghai Yangzhi Rehabilitation Hospital. A total of 48 patients with PD and 17 healthy controls who visited the hospital between July 2021 and August 2024 were included. Participants in both groups were matched for gender, age, and body mass index (BMI). All participants provided informed consent, and the study protocol was approved by the Ethics Committee of Shanghai Yangzhi Rehabilitation Hospital (Approval Number: MCSC-2025-001). Due to the retrospective nature of the study, informed consent was waived for the use of anonymized, previously collected clinical data, in accordance with ethical standards. Inclusion criteria for the PD group:(1)Diagnosis based on the UK Parkinson's Disease Society Brain Bank Criteria [11], exhibiting progressive motor symptoms (including at least two of the three core symptoms: resting tremor, bradykinesia, and rigidity).༈2༉Ability to comprehend study content and provide informed consent.༈3༉Ability to safely undergo CPET as assessed by a specialist. Exclusion criteria for both groups:(1)Presence of severe cardiovascular or cerebrovascular diseases (e.g., myocardial infarction, unstable angina within the past 3 months, NYHA Class III-IV heart failure).༈2༉Uncontrolled hypertension (systolic blood pressure > 160 mmHg) or diabetes (fasting blood glucose > 10 mmol/L).༈3༉Presence of other neurological disorders (e.g., stroke, dementia, epilepsy).༈4༉Joint diseases affecting motor function or other exercise contraindications (e.g., pulmonary embolism, severe aortic stenosis, malignant arrhythmia). General Information The study collected demographic and health-related variables, including gender, age, education level, BMI, and comorbidities. For the PD group, additional clinical data were recorded, including disease duration and levodopa equivalent daily dose (LEDD)[12]. Disease severity was assessed by a neurologist using the Modified Hoehn-Yahr Staging System[13], a 5-stage scale evaluating the progression of PD symptoms, and the Unified Parkinson’s Disease Rating Scale III (UPDRS-III)[14], which measures the severity of motor symptoms. Activities of daily living were evaluated using the Modified Barthel Index (MBI)[15], and cognitive function was assessed using the Montreal Cognitive Assessment (MoCA)[16], a tool validated for use in the Chinese population[17]. Cardiopulmonary Fitness Assessment All participants were instructed to refrain from consuming caffeinated beverages (coffee, tea, cola, etc.) for 12 hours prior to testing. To ensure optimal performance during the test, participants took their regular medication one hour before the test to be in an "on" state. The CPET was conducted using a specific system with a 12-lead electrocardiogram, blood oxygen saturation monitoring, non-invasive blood pressure measurement, and respiratory gas analysis[18]. The testing protocol included the following phases[19]:(1)Preparation Phase: Exclusion of contraindications for exercise, collection of medical history, and confirmation of informed consent.༈2༉Baseline Assessment: Static PFT.༈3༉Exercise Testing: Ramp incremental load protocol on a cycle ergometer, with the load adjusted according to individual tolerance. The test phases were:Rest Phase: 3 minutes of baseline heart rate, blood pressure, oxygen saturation, and electrocardiogram data;Warm-up Phase: 3 minutes maintaining a pedal frequency of 55–65 revolutions per minute༛Load Phase: 8–12 minutes of incremental load according to the preset protocol, with continuous physiological monitoring༛Recovery Phase: 3 minutes of post-exercise recovery, assessing fatigue using the Borg Rating of Perceived Exertion (RPE) scale[20]. Exercise Termination Criteria The exercise test was terminated immediately upon the occurrence of any of the following conditions:(1)Inability to maintain pedaling cadence.༈2༉Symptoms of chest pain, dizziness, visual disturbances, pallor, or cyanosis.༈3༉Abnormal blood pressure (systolic blood pressure > 180 mmHg, diastolic blood pressure > 120 mmHg, or a systolic blood pressure drop > 10 mmHg).༈4༉Electrocardiogram ST segment depression (≥ 0.1 mV horizontal or downsloping or ≥ 0.2 mV upsloping).༈4༉Severe arrhythmias (e.g., frequent premature ventricular contractions, polymorphic ventricular tachycardia, or supraventricular tachycardia) Statistical Analysis Data analysis was performed using SPSS 26.0 software and graphpad prism9. Continuous variables were first tested for normality using the Shapiro-Wilk test. Data with normal distribution were presented as means ± standard deviation, and group comparisons were conducted using independent sample t-tests. Non-normally distributed data were presented as median (interquartile range) and analyzed using the Mann-Whitney U test. Categorical variables were expressed as frequencies (%) and compared using the chi-squared test or Fisher's exact test. Correlation analyses employed Pearson's test for normal data and Spearman's test for non-normal distributions.All statistical tests were two-tailed, and a p-value of < 0.05 was considered statistically significant. Results The study included 48 patients with PD and 17 age-matched controls. No significant differences were observed in baseline demographics or Clinical Characteristics between the two groups. Among PD patients, the median disease duration was 6.50 years (IQR: 4.50–10.50).The majority of PD participants were classified as H-Y stage 3 (37.5%) or stage 4 (27.1%). The cohort demonstrated moderate motor impairment, with a median UPDRS-III score of 29.5 (IQR: 20.0–38.0). ( shown in Table 1 ) Table 1 Demographic and clinical characteristics of PD patients and controls Characteristics PD Group (n = 48) ControlGroup (n = 17) Test Statistic P-value Demographics Age, years 69.0 (65.0,72.5) 66.0 (62.0,69.0) -1.556ᵈ 0.120 Male, n (%) 21 (67.7) 27 (79.4) 1.143ᵇ 0.285 BMI, kg/m² 23.54 ± 3.32 23.44 ± 3.35 0.107ᵃ 0.915 Vital signs HRrest, bpm 83.31 ± 11.15 83.25 ± 11.65 0.006ᵃ 0.995 SBPrest, mmHg 124.46 ± 14.96 121.53 ± 14.83 0.695ᵃ 0.489 DBPrest, mmHg 75.79 ± 10.01 81.53 ± 12.30 -1.91ᵃ 0.061 Comorbidities, n (%) Heart disease 2 (4.2) 3 (17.6) -ᶜ 0.107 Syncope history 6 (12.6) 0 (0.0) -ᶜ 0.327 Hyperlipidemia 10 (20.8) 3 (17.6) -ᶜ 0.745 Diabetes 10 (20.8) 3 (17.6) -ᶜ 0.745 Hypertension 15 (31.3) 3 (17.6) -ᶜ 0.357 Stroke 4 (8.3) 2 (11.8) -ᶜ 0.648 Smoking history 4 (8.3) 4 (23.5) -ᶜ 0.191 Alcohol use 2 (6.2) 2 (11.8) -ᶜ 0.107 Disease-specific data Disease duration, years 6.50 (4.50,10.50) - - - H-Y stage, n (%) Stage 1 3 (6.3) - - - Stage 1.5 2 (4.2) - - - Stage 2 9 (18.8) - - - Stage 2.5 3 (6.3) - - - Stage 3 18 (37.5) - - - Stage 4 13 (27.1) - - - UPDRS-III score 29.5 (20.0,38.0) - - - Abbreviations: BMI:body mass index; HRrest:resting heart rate; SBP/DBP:systolic/diastolic blood pressure; H-Y :Hoehn & Yahr; UPDRS-III: Unified Parkinson’s Disease Rating Scale Part III; Statistical notations: ᵃ Independent samples t-test;ᵇ Pearson's chi-square test;ᶜ Fisher's exact test;ᵈ Mann-Whitney U test (Z-score reported) PFT revealed significant impairments in PD patients compared to controls across several parameters. PD patients exhibited markedly reduced forced vital capacity (FVC) (2.21 ± 0.72 L vs 3.08 ± 0.86 L, p < 0.001; 75.46 ± 18.91% vs 88.41 ± 14.17% predicted, p = 0.013) and forced expiratory volume in 1 second (FEV₁) (1.71 ± 0.57 L vs 2.51 ± 0.70 L, p < 0.001; 73.46 ± 18.04% vs 87.76 ± 14.53% predicted, p = 0.005). The FEV₁/FVC ratio showed a trend towards obstruction in PD patients (median 77.40% vs 81.25%, p = 0.059), although this difference did not reach statistical significance.Maximum ventilatory capacity (MVV) was severely compromised in PD patients, with MVV values being approximately 60% of those in controls (51.01 ± 22.08% vs 82.67 ± 29.34% predicted, p < 0.001). Mid-expiratory flows were significantly reduced at 50% of FVC (MEF₅₀: 2.28 L/s vs 3.92 L/s, p < 0.001; 63.00% vs 86.50% predicted, p = 0.001). However, differences at 25% of FVC (MEF₂₅) were not significant (0.70 L/s vs 1.09 L/s, p = 0.236).Measures of diffusion capacity, including Diffusing capacity of the lungs for carbon monoxide(DLCO) (12.74 vs 13.25 mL/min/mmHg, p = 0.140) and Diffusing capacity per unit alveolar volume (DLCO/Vₐ )(4.36 vs 5.04 mL/min/mmHg/L, p = 0.182), showed no significant differences between the groups, nor did their percent predicted values (all p > 0.05). (shown in Table 2 ) Table 2 Comparison of PFT between PD patients and controls Variable (Unit) PD Group (n = 48) Control Group (n = 17) Test Statistic P-value FVC (L) 2.21 ± 0.72 3.08 ± 0.86 -4.055ᵃ < 0.001 FVC (% predicted) 75.46 ± 18.91 88.41 ± 14.17 -2.563ᵃ 0.013 FEV₁ (L) 1.71 ± 0.57 2.51 ± 0.70 -4.660ᵃ < 0.001 FEV₁ (% predicted) 73.46 ± 18.04 87.76 ± 14.53 -2.932ᵃ 0.005 FEV₁/FVC ratio (%) 77.40 (69.30,81.20) 81.25 (78.40,84.60) -1.889ᵈ 0.059 FEV₁/FVC (% pred.) 103.00 (92.00,108.00) 102.00 (98.00,108.50) -0.705ᵈ 0.481 MVV (% predicted) 51.01 ± 22.08 82.67 ± 29.34 -4.610ᵃ < 0.001 MEF₅₀ (L/s) 2.28 (1.58,2.51) 3.92 (2.79,4.46) -4.143ᵈ < 0.001 MEF₅₀ (% predicted) 63.00 (43.00,74.00) 86.50 (62.50,104.50) -3.399ᵈ 0.001 MEF₂₅ (L/s) 0.70 (0.46,0.83) 1.09 (0.88,1.63) -1.185ᵈ 0.236 MEF₂₅ (% predicted) 58.00 (42.00,73.00) 72.00 (43.50,86.50) -1.347ᵈ 0.178 DLCO (mL/min/mmHg) 12.74 (5.65,16.94) 13.25 (10.56,22.63) -1.478ᵈ 0.140 DLCO (% predicted) 56.00 (25.00,68.00) 47.50 (37.50,79.50) -0.108ᵈ 0.914 DLCO/Vₐ (mL/min/mmHg/L) 4.36 (3.65,5.33) 5.04 (3.87,5.34) -1.333ᵈ 0.182 DLCO/Vₐ (% predicted) 99.00 (83.00,124.00) 106.00 (90.00,117.00) -0.605ᵈ 0.545 Abbreviations: FVC: Forced vital capacity;FEV₁: Forced expiratory volume in 1 second;MVV: Maximum voluntary ventilation;MEF₅₀/FEF₅₀: Maximum expiratory flow at 50% of FVC;MEF₂₅/FEF₂₅: Maximum expiratory flow at 25% of FVC;DLCO: Diffusing capacity of the lungs for carbon monoxide (adjusted for hemoglobin);DLCO/Vₐ: Diffusing capacity per unit alveolar volume;% predicted: Percentage of predicted normal values PD patients exhibited significantly lower peak oxygen consumption compared to controls. The median peakVO₂ was 770.00 mL/min in the PD group versus 1066.50 mL/min in the control group (p = 0.006), and peak VO₂/kg was also lower in PD patients (13.25 vs 17.10 mL/min/kg, p = 0.002). Additionally, PD patients demonstrated reduced peak work capacity (41.50 vs 80.00 watts, p < 0.001), substantially shorter exercise duration (9.17 vs 16.00 minutes, p = 0.004), and lower peak minute ventilation (26.50 vs 41.00 L/min, p < 0.001).Notably, PD patients exhibited a blunted chronotropic response, with significantly lower peak heart rate (110.50 vs 139.41 bpm, p < 0.001) and a trend toward reduced heart rate at the anaerobic threshold (103.28 vs 113.82 bpm, p = 0.065). The respiratory exchange ratio was significantly lower in PD patients (1.02 vs 1.15, p < 0.001), suggesting reduced maximal effort or a ventilatory limitation.Despite achieving lower workloads, PD patients reported higher perceived exertion, with a median Rating of Perceived Exertion (RPE) of 17 versus 15 in controls (p = 0.094). Hemodynamic responses also differed between groups, with PD patients showing significantly lower peak systolic blood pressure (160.10 vs 176.88 mmHg, p = 0.020).Oxygen pulse and breathing reserve were comparable between groups (both p > 0.05), indicating that stroke volume contribution to oxygen delivery and ventilatory capacity relative to demand was preserved in PD patients. (shown in Table 3 ) Table 3 Comparison of CPET parameters between PD patients and controls Parameter PD Group (n = 48) Control Group (n = 17) Test Statistic P-value PeakVO₂ (mL/min) 770.00 (653.00,1004.50) 1066.50 (749.00,1317.50) -2.747ᵈ 0.006 PeakVO₂(% predicted) 58.00 (48.00,67.00) 53.50 (49.00,62.50) -0.022ᵈ 0.982 PeakVO₂/kg (mL/min/kg) 13.25 (10.45,16.00) 17.10 (13.70,19.80) -3.061ᵈ 0.002 VO₂atAT (mL/min) 664.50 (549.00,856.50) 757.00 (586.00,949.00) -1.502ᵈ 0.133 VO₂atAT (% predicted) 50.90 (39.75,57.90) 41.55 (38.30,49.50) -1.397ᵈ 0.162 VO₂/kgatAT (mL/min/kg) 11.40 ± 3.61 12.92 ± 3.25 -1.514ᵃ 0.135 METspeak (METs) 4.10 (3.25,4.50) 5.10 (4.30,6.20) -3.219ᵈ 0.001 METsat AT (METs) 3.38 ± 1.05 3.86 ± 1.13 -1.562ᵃ 0.123 O₂pulse (mL/beat) 7.43 ± 2.42 7.62 ± 2.59 -0.239ᵃ 0.812 O₂pulse (% predicted) 77.94 ± 15.47 74.88 ± 15.30 0.671ᵃ 0.505 Peak VE (L/min) 26.50 (22.50,35.50) 41.00 (28.50,47.50) -3.483ᵈ < 0.001 BR (%) 61.46 ± 15.25 58.38 ± 19.36 0.655ᵃ 0.515 RER 1.02 ± 0.08 1.15 ± 0.10 -5.089ᵃ < 0.001 HR at AT (bpm) 103.28 ± 13.82 113.82 ± 20.73 -1.947ᵃ 0.065 HRpeak (bpm) 110.50 ± 15.18 139.41 ± 26.63 -4.239ᵃ < 0.001 HRpeak (% predicted) 75.03 ± 10.82 79.82 ± 22.49 -1.156ᵃ 0.252 HRR (bpm) 38.15 ± 16.41 29.18 ± 15.58 1.956ᵃ 0.055 SBPpeak(mmHg) 160.10 ± 22.81 176.88 ± 30.27 -2.386ᵃ 0.020 DBPpeak (mmHg) 79.38 ± 12.40 82.29 ± 18.25 -0.733ᵃ 0.466 Exercise duration (min) 9.17 (5.27,13.72) 16.00 (7.19,18.88) -2.858ᵈ 0.004 WR at AT (watt) 31.00 (16.50,44.50) 50.50 (37.50,72.00) -3.299ᵈ 0.001 WRpeak (watt) 41.50 (25.00,57.50) 80.00 (51.50,126.00) -3.720ᵈ < 0.001 RPE (Borg Scale) 17.00 (15.00,17.00) 15.00 (13.00,17.00) -1.674ᵈ 0.094 Dyspnea (Borg Scale) 5.00 (3.00,7.00) 5.00 (2.50,6.00) -0.912ᵈ 0.360 Abbreviations : VO₂ : Oxygen uptake; AT : Anaerobic threshold; METs : Metabolic equivalents (1 MET = 3.5 mL O₂/kg/min); O₂ pulse : Oxygen uptake per heart beat (stroke volume × arteriovenous O₂ difference); VE : Minute ventilation; BR : Breathing reserve; RER : Respiratory exchange ratio (VCO₂/VO₂); HR : Heart rate; HRR : Heart rate recovery; SBP/DBP : Systolic/diastolic blood pressure; WR : Work rate; RPE : Rating of perceived exertion (Borg Scale 6–2 PF parameters demonstrated significant correlations with key CPET variables in patients with PD. FVC and FEV₁ exhibited strong positive associations with peak VO₂(r = 0.787 and 0.795, respectively; P < 0.01), workload at anaerobic threshold (WR at AT) (r = 0.667 and 0.611; P < 0.01), and peak workload (WRpeak) (r = 0.740 and 0.726; P < 0.01).Similarly, maximal voluntary ventilation (MVV) showed moderate correlations with peak VO₂/kg (r = 0.554, P < 0.01), METs at peak exercise (METspeak) (r = 0.583, P < 0.01), and peak ventilation (Vepeak) (r = 0.505, P < 0.01).Notably, percent-predicted values (e.g., FVC% predicted and FEV₁% predicted) displayed divergent patterns. While FEV₁% predicted was positively associated with METs at peak exercise (METspeak) (r = 0.520, P < 0.01) and systolic blood pressure at peak exercise (SBPpeak) (r = 0.364, P < 0.05), FVC% predicted showed negative correlations with METspeak (r = − 0.383, P < 0.01) and peak VO₂/kg (r = − 0.356, P < 0.05).Mid-expiratory flow rates (MEF₅₀, MEF₅₀%) also exhibited significant correlations with exercise capacity metrics (r = 0.434–0.475, P < 0.01). (shown in Table 4 and Fig. 1) Table 4 Correlation between PFT and CPET parameters in PD Pulmonary Parameter peakVO₂ peakVO₂/kg METspeak VEpeak RER HRpeak SBPpeak Exercise duration WR at AT WRpeak FVC 0.787 **S 0.515 **S 0.417 **S 0.687 **S 0.025 P 0.164 P 0.172 P 0.511 **S 0.667 **S 0.740 **S FVC% pred -0.209 S -0.356 *S -0.383 **S -0.185 S -0.022 P 0.293 *P 0.391 **P -0.280 S 0.094 P 0.062 P FEV₁ 0.795 **S 0.586 **S 0.533 **S 0.675 **S 0.361 *P 0.220 P 0.240 P 0.502 **S 0.611 **S 0.726 **S FEV₁% pred 0.360 *S 0.462 **S 0.520 **S 0.318 *S 0.198 P 0.300 *P 0.364 *P 0.368 *S 0.144 P 0.185 P MVV 0.501 **S 0.554 **S 0.583 **S 0.505 **S 0.264 P 0.474 **P 0.304 *P 0.341 *S 0.384 *S 0.423 *S MEF50 0.465 **S 0.354 *S 0.434 **S 0.389 **S 0.264 P 0.474 **P 0.304 *P -0.203 S 0.269 S 0.333 *S MEF50 (% predicted) 0.422 **S 0.403 **S 0.475 **S 0.373 *S 0.356 *P 0.234 P 0.288 P 0.228 S 0.220 S 0.286 S Abbreviations: **P < 0.01; *P < 0.05; P = Pearson's correlation ;S = Spearman's rank correlation The assessment of PF and exercise capacity in our PD cohort revealed significant impairment patterns. This disparity between relatively preserved PF (84% of patients with FEV₁ ≥50% predicted) and markedly impaired exercise capacity (96% with peakVO₂ <20 mL/kg/min) suggests that factors beyond pulmonary limitation contribute significantly to reduced exercise tolerance in PD. (shown in Table 5 ) Table 5 Distribution of PF and exercise capacity severity in PD patients Parameter Severity Category Frequency (n) Percentage (%) FEV₁ (% predicted) > 80% (normal) 21 43.8 50–80% (moderate) 20 41.7 20 (normal) 2 4.2 15–20 (mild) 14 29.2 < 15 (severe) 32 66.7 Total 48 100.0 Patients with higher aerobic capacity (VO₂peak ≥ 15 mL/kg/min, n = 16) were more likely to be male (68.8% vs. 31.3%, p = 0.014) and had better cognitive function (MoCA: 27.0 vs. 22.0, p = 0.007) and daily living scores (MBI: 94.0 vs. 78.5, p = 0.020) compared to those with VO₂peak < 15 (n = 32). The low aerobic capacity group had higher H&Y stage (p = 0.044), suggesting greater disease severity. No significant differences were found in age, BMI, disease duration, UPDRS-III, or cardiovascular measures (p > 0.05). ( shown in Table 6 ) Table 6 Clinical characteristics by aerobic capacity groups (VO₂peak ≥ 15 vs < 15 mL/kg/min) Characteristic VO₂peak ≥ 15 (n = 16) VO₂peak < 15 (n = 32) Test Statistic P-value Demographics Male, n (%) 11 (68.8) 10 (31.3) 6.095ᵇ 0.014* Age (years) 65.1 ± 8.4 68.8 ± 5.5 -1.853ᵃ 0.070 BMI (kg/m²) 23.0 ± 2.4 23.8 ± 3.7 -0.823ᵃ 0.414 Clinical Measures Disease duration (years) 5.0 (5.0-11.5) 7.0 (4.5-9.0) 0.040ᵈ 0.969 H&Y stage 3.0 (2.0–3.0) 3.0 (2.3-4.0) -2.017ᵈ 0.044* UPDRS-III 24.0 (20.0-36.5) 32.0 (21.5–39.5) -1.106ᵈ 0.269 Functional Scores MoCA 27.0 (24.0–28.0) 22.0 (19.0–26.0) -2.679ᵈ 0.007** MBI 94.0 (82.0–95.0) 78.5 (65.0–93.0) -2.333ᵈ 0.020* Physiological Parameters HRrest (bpm) 84.7 ± 12.2 82.6 ± 10.7 0.600ᵃ 0.551 SBPrest (mmHg) 121.1 ± 10.7 126.1 ± 16.6 -1.094ᵃ 0.280 DBPrest (mmHg) 74.9 ± 8.1 76.2 ± 10.9 -0.414ᵃ 0.681 LEDD (mg) 571.6 ± 300.9 567.3 ± 297.5 0.048ᵃ 0.962 Abbreviations:MoCA: Montreal Cognitive AssessmentMBI: Modified Barthel Index (activities of daily living)LEDD: Levodopa equivalent daily dose Discusion This study aimed to investigate the relationship between PTF, CRF, and clinical outcomes in patients with PD. Our findings reveal that PD patients exhibit significant deficits in both pulmonary ventilation function and aerobic capacity compared to healthy controls. These deficits are closely related to clinical symptoms, disease progression, and quality of life, suggesting that the decline in cardiopulmonary function plays a important role in the non-motor manifestations of PD. Our study demonstrated significant impairments in static PF in PD patients compared to healthy controls, including reduced FVC, FEV₁, and MVV, along with decreased MEF50. These findings suggest a mixed pattern of restrictive and obstructive ventilatory dysfunction in PD.The observed restrictive pattern (evidenced by reduced FVC and FEV₁ with preserved FEV₁/FVC ratio) may be attributed to thoracic rigidity, postural abnormalities (e.g., kyphosis), and respiratory muscle weakness, as previously reported in PD patients[21]. Additionally, the obstructive component (reflected by significantly lower MEF₅₀) could stem from peripheral airway obstruction due to oropharyngeal muscle dysfunction, autonomic dysregulation, or upper airway collapse[22]. Notably, while the FEV₁/FVC ratio did not reach statistical significance, the trend toward reduction aligns with studies highlighting heterogeneous airway involvement in PD.The marked decline in MVV further underscores the combined impact of respiratory muscle fatigue and reduced lung compliance, potentially exacerbating dyspnea and exercise intolerance in this population[22]. CPET further confirmed the severity of these impairments, with PD patients exhibiting significantly lower CRF, as well as an earlier onset of anaerobic threshold (AT). These results reflect a marked impairment in aerobic metabolism and align with findings, which reported a 30% reduction in VO₂peak in PD patients compared to healthy individuals, indicating limited cardiopulmonary adaptation during high-intensity exercise[18, 23]. Additionally, a delayed physiological response during exercise was observed, as evidenced by reduced peak heart rate, peak ventilation, and respiratory exchange ratio (RER) in PD patients, consistent with the results of Kanegusuku et al[24]. In addition to these findings, we performed correlation analyses between static PF and CPET parameters. These correlations suggest that PF plays a crucial role in exercise performance, with better lung function linked to higher levels of exercise capacity. Respiratory muscle training (RMT) has been shown to significantly improve aerobic capacity in PD. High-intensity RMT, involving daily training of both inspiratory and expiratory muscles, enhances maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), improving endurance, dyspnea, fatigue, and quality of life. These improvements indicate that respiratory muscle function is closely related to better exercise capacity, particularly for aerobic activities [25].Systematic reviews and meta-analyses confirm that RMT improves respiratory function markers like peak expiratory flow rate (PEFR), which directly impacts physical performance. While MIP improvements are less pronounced, RMT's overall positive effects on exercise capacity are evident [26]. Additionally, inspiratory muscle training (IMT) has been shown to improve upper limb function and reduce fatigue, further supporting its value in PD treatment [27].The Parkinson's Foundation also recommends deep breathing exercises to enhance lung function and aerobic capacity in PD patients, reinforcing the importance of integrating these exercises into rehabilitation programs[28]. Our study further analyzed the clinical correlation between CRF and PTF results, revealing that despite moderate levels of lung function preservation, 96% of PD patients exhibited severe limitations in aerobic endurance. This phenomenon suggests that exercise intolerance is not solely attributable to pulmonary restriction, but is also significantly influenced by various "extrathoracic mechanisms." First, autonomic dysfunction, a common non-motor feature in PD, affects key physiological processes during exercise, including heart rate, blood pressure, and ventilation responses. We observed that PD patients had significantly lower peak heart rate (HRpeak), peak systolic blood pressure (SBPpeak), and RER compared to controls, reflecting limited sympathetic activation[18]. The absence of appropriate cardiovascular responses during exercise severely impairs oxygen delivery efficiency, leading to early fatigue and premature cessation of physical activity. Additionally, peripheral muscle metabolic dysfunction and impaired oxygen utilization further limit the exercise capacity in PD patients. Mitochondrial dysfunction, decreased capillary density, and muscle mass loss in PD contribute to a reduced ability of skeletal muscles to uptake and utilize oxygen (a-v O₂ difference), limiting VO₂peak even when pulmonary oxygen supply is adequate[29]. Furthermore, postural abnormalities (such as forward neck flexion and thoracic posture) restrict chest expansion, and muscle rigidity reduces the flexibility of respiratory muscles, leading to increased perceived exertion (RPE) even under lower exercise loads. It is also noteworthy that psychological and cognitive factors play a significant role in these extrathoracic mechanisms. Our study found that patients with higher VO₂peak performed better in MoCA and MBI scores, indicating that cognitive function and activities of daily living are closely linked to exercise endurance. PD is often accompanied by depression, apathy, and executive dysfunction, which may reduce motivation and subjective effort levels, leading patients to experience fatigue before reaching their physiological limits, thus limiting their actual exercise performance. This study also found that, despite some differences in clinical indicators such as disease duration and UPDRS-III scores in PD patients, these factors did not show significant correlations with changes in cardiopulmonary function. This finding is consistent with the results of Wang et al. (2024), who reported that the decline in cardiopulmonary function in PD patients occurs universally, regardless of the disease duration, and is not solely dependent on clinical staging or medication. Furthermore, good CRF appears to have a positive impact on the cognitive function and daily living abilities of PD patients. Our study found that patients with a VO₂peak greater than 15 mL/kg/min scored better on cognitive function (MoCA score) and daily living abilities (MBI score) than those with a VO₂peak less than 15 mL/kg/min. Research by Schenkman et al [5]in their study on the effects of high-intensity aerobic exercise intervention in PD patients showed similar findings, indicating that improving CRF can effectively improve both cognitive and functional status in PD patients. Based on these findings, the decline in cardiopulmonary fitness in PD patients is a result of multiple synergistic factors, highlighting the central role of individualized exercise prescriptions in PD rehabilitation. Traditional pulmonary function assessments are insufficient to fully reflect the functional status of PD patients. Therefore, we recommend the widespread use of CPET in clinical practice to identify limiting factors and develop personalized exercise prescriptions. Additionally, interventions such as autonomic nervous system training, RMT, resistance training, and psychological rehabilitation can help break the vicious cycle of "exercise function limitation—decline in physical capacity," improving cardiopulmonary health and quality of life. Compared to traditional standardized programs, personalized interventions based on CRF assessment can more accurately match the patient’s physiological status and disease characteristics, significantly improving VO₂peak and exercise endurance. For patients with poor exercise function, low-intensity aerobic training combined with RMT can be used, while for those with better exercise function, the intensity can be gradually increased to further improve CRF and help delay disease progression[30]. However, our study has some limitations. Its cross-sectional design precludes causal inference, and the applicability of CPET may be limited in advanced PD stages. Future longitudinal studies should focus on the progression of central pulmonary dysfunction in PD and evaluate the long-term effects of exercise interventions on CRF and disease progression. Conclusions Our study demonstrates that PD patients experience significant declines in both PF and CRF, which are associated with worse clinical and functional outcomes. The observed dissociation between preserved pulmonary function and impaired CRF suggests that exercise intolerance in PD is primarily driven by factors beyond pulmonary limitations, such as neuromuscular dysfunction and autonomic imbalance. Integrating CRF assessments into clinical practice and developing individualized rehabilitation programs can help break the "motor dysfunction-cardiopulmonary decline" vicious cycle and provide more comprehensive treatment options for PD patients. Future research should further explore how targeted exercise interventions can improve CRF and optimize clinical outcomes for PD patients. Abbreviations PD Parkinson's Disease CRF Cardiorespiratory Fitness PF Pulmonary Function PFT Pulmonary Function Testing CPET Cardiopulmonary Exercise Testing VO₂peak Peak Oxygen Uptake METs Metabolic Equivalents (1 MET = 3.5 mL O₂/kg/min) HRrest Resting Heart Rate SBP Systolic Blood Pressure DBP Diastolic Blood Pressure FVC Forced Vital Capacity FEV₁ Forced Expiratory Volume in 1 second MVV Maximum Voluntary Ventilation MEF₅₀ Maximum Expiratory Flow at 50% of FVC MEF₂₅ Maximum Expiratory Flow at 25% of FVC DLCO Diffusing Capacity of the Lungs for Carbon Monoxide DLCO/Vₐ Diffusing Capacity per Unit Alveolar Volume RPE Rating of Perceived Exertion (Borg Scale) HRpeak Peak Heart Rate WR Work Rate AT Anaerobic Threshold BPM Beats Per Minute MBI Modified Barthel Index (Activities of Daily Living) MoCA Montreal Cognitive Assessment LEDD Levodopa Equivalent Daily Dose H-Y Hoehn & Yahr UPDRS-III Unified Parkinson’s Disease Rating Scale Part III BMI Body Mass Index RER Respiratory Exchange Ratio VE Minute Ventilation BR Breathing Reserve HRR Heart Rate Recovery DLCO/Vₐ (% predicted) Percentage of Predicted Diffusing Capacity per Unit Alveolar Volume FVC (% predicted) Percentage of Predicted Forced Vital Capacity FEV₁ (% predicted) Percentage of Predicted Forced Expiratory Volume in 1 second DLCO Diffusing Capacity of the Lungs for Carbon Monoxide (adjusted for hemoglobin) WRpeak Peak Work Rate VO₂ at AT Oxygen Uptake at Anaerobic Threshold VO₂/kg at AT Oxygen Uptake per Kilogram at Anaerobic Threshold PEFR Peak Expiratory Flow Rate Declarations Ethics approval and consent to participate Not applicable. This retrospective cross-sectional study was conducted in accordance with the ethical standards of the institutional research committee and the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Ethical approval was waived by the Medical Ethics Committee of Shanghai Yangzhi Rehabilitation Hospital due to the retrospective nature of the study (Approval Number: MCSC-2025-001). As this study used anonymized, previously collected clinical data, the requirement for informed consent was also waived by the same committee. Consent for publication Not applicable. Availability of data and materials The datasets generated and/or analyzed during the current study are available from the corresponding author ( Yu-Zhen Chen ) upon reasonable request and subject to a signed data access agreement. Requests can be made via institutional email. Competing interests The authors declare no competing interests. Funding The study was supported by the National Key Clinical Specialty Discipline Construction Project of China (Z155080000004), the Shanghai Research Center of Rehabilitation Medicine – Top Priority Research Center of Shanghai (2023ZZ02027), the Shanghai Clinical Research Ward Project (SHDC2023CRW018B), the Shanghai Hospital Development Center Foundation – Shanghai Municipal Hospital Rehabilitation Medicine Specialty Alliance (SHDC22023304),the Shanghai Yangzhi Rehabilitation Hospital(2024QNRC14),.and the Shanghai Yangzhi Rehabilitation Hospital(2023QNRC11). Authors' contributions Yu-Zhen Chen and Qin Zhao co-first authors and contributed equally to this work. Guarantor of integrity of the entire study: Yu-Zhen Chen, Qin Zhao. Study concepts: Yu-Zhen Chen, Qin Zhao. Study design: Yu-Zhen Chen，Ling-Jing Jin .Data acquisition: Yu-Zhen Chen, Lu Wei, Shuang-Fang Li, Hong Zhang，Yue Li. Data analysis: Yu-Zhen Chen，Dan-Mei Lan. Manuscript preparation: Yu-Zhen Chen. Manuscript editing: Yu-Zhen Chen, Qin Zhao. Manuscript review: Qin Zhao, Ling-Jing Jin. Acknowledgements Not applicable. Authors’ information Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital, Shanghai, 201619, China;Yu-Zhen Chen & Dan-Mei Lan, & Yue Li,& Lu Wei & Shuang-Fang Li & Hong Zhang; Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital, School of Medicine, Tongji University, Shanghai, 201619, China.;Qin Zhao & Ling-Jing Jin References Pechstein AE, Gollie JM, Guccione AA. Fatigability and Cardiorespiratory Impairments in Parkinson's Disease: Potential Non-Motor Barriers to Activity Performance. J Funct Morphol Kinesiol. 2020;5(4). Aburub A, Ledger SJ, Sim J, Hunter SM. Cardiopulmonary Function and Aerobic Exercise in Parkinson's: A Systematic Review of the Literature. Mov Disord Clin Pract. 2020;7(6):599–606. Cruickshank TM, Reyes AR, Ziman MR. A systematic review and meta-analysis of strength training in individuals with multiple sclerosis or Parkinson disease. Medicine. 2015;94(4):e411. Ahlskog JE. Does vigorous exercise have a neuroprotective effect in Parkinson disease? Neurology. 2011;77(3):288 − 94. Schenkman M, Moore CG, Kohrt WM, Hall DA, Delitto A, Comella CL, et al. Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial. JAMA Neurol. 2018;75(2):219 − 26. Penko AL, Zimmerman NM, Crawford M, Linder SM, Alberts JL. Effect of Aerobic Exercise on Cardiopulmonary Responses and Predictors of Change in Individuals With Parkinson's Disease. Arch Phys Med Rehabil. 2021;102(5):925 − 31. Balady GJ, Arena R, Sietsema K, Myers J, Coke L, Fletcher GF, et al. Clinician's Guide to cardiopulmonary exercise testing in adults: a scientific statement from the American Heart Association. Circulation. 2010;122(2):191–225. Kanegusuku H, Silva-Batista C, Peçanha T, Nieuwboer A, Silva ND Jr, Costa LA, et al. Blunted Maximal and Submaximal Responses to Cardiopulmonary Exercise Tests in Patients With Parkinson Disease. Arch Phys Med Rehabil. 2016;97(5):720-5. McMahon L, McGrath D, Blake C, Lennon O. Responsiveness of respiratory function in Parkinson's Disease to an integrative exercise programme: A prospective cohort study. PLoS One. 2024;19(3):e0301433. Sabino-Carvalho JL, Vianna LC. Altered cardiorespiratory regulation during exercise in patients with Parkinson's disease: A challenging non-motor feature. SAGE Open Med. 2020;8:2050312120921603. Devos D, Hirsch E, Wyse R. Seven Solutions for Neuroprotection in Parkinson's Disease. Mov Disord. 2021;36(2):306 − 16. Tomlinson CL, Stowe R, Patel S, Rick C, Gray R, Clarke CE. Systematic review of levodopa dose equivalency reporting in Parkinson's disease. Mov Disord. 2010;25(15):2649-53. Goetz CG, Poewe W, Rascol O, Sampaio C, Stebbins GT, Counsell C, et al. Movement Disorder Society Task Force report on the Hoehn and Yahr staging scale: status and recommendations. Mov Disord. 2004;19(9):1020-8. Martínez-Martín P, Gil-Nagel A, Gracia LM, Gómez JB, Martínez-Sarriés J, Bermejo F. Unified Parkinson's Disease Rating Scale characteristics and structure. The Cooperative Multicentric Group. Mov Disord. 1994;9(1):76–83. Shah S, Vanclay F, Cooper B. Improving the sensitivity of the Barthel Index for stroke rehabilitation. J Clin Epidemiol. 1989;42(8):703-9. Xu Q, Zhou M, Jiang C, Wu L, He Q, Zhao L, et al. Application of the Chinese Version of the Montreal Cognitive Assessment-Basic for Assessing Mild Cognitive Impairment in Parkinson's Disease. Brain Sci. 2021;11(12). National Institute for Health and Care Excellence. Parkinson's disease in adults: diagnosis and management. London: National Institute for Health and Care Excellence (NICE); 2017. Wang K, Cheng H, Yang B, Liu D, Maria M, Wu Q, et al. Assessment of cardiorespiratory fitness in Chinese patients with early to mid-stage Parkinson's disease. Int J Neurosci. 2024:1–10. Guazzi M, Arena R, Halle M, Piepoli MF, Myers J, Lavie CJ. 2016 Focused Update: Clinical Recommendations for Cardiopulmonary Exercise Testing Data Assessment in Specific Patient Populations. Circulation. 2016;133(24):e694-711. Ding W, You T, Gona PN, Milliken LA. Validity and reliability of a Chinese rating of perceived exertion scale in young Mandarin speaking adults. Sports Med Health Sci. 2020;2(3):153-8. De Pandis MF, Starace A, Stefanelli F, Marruzzo P, Meoli I, De Simone G, et al. Modification of respiratory function parameters in patients with severe Parkinson's disease. Neurol Sci. 2002;23 Suppl 2:S69-70. Hammer MJ, Barlow SM. Laryngeal somatosensory deficits in Parkinson's disease: implications for speech respiratory and phonatory control. Exp Brain Res. 2010;201(3):401-9. Speelman AD, Groothuis JT, van Nimwegen M, van der Scheer ES, Borm GF, Bloem BR, et al. Cardiovascular responses during a submaximal exercise test in patients with Parkinson's disease. J Parkinsons Dis. 2012;2(3):241-7. Kanegusuku H, Cucato GG, Longano P, Okamoto E, Piemonte MEP, Correia MA, et al. Acute Cardiovascular Responses to Self-selected Intensity Exercise in Parkinson's Disease. Int J Sports Med. 2022;43(2):177 − 82. Brito SAF, Scianni AA, Silveira BMF, Oliveira ERM, Mateus ME, Faria C. Effects of high-intensity respiratory muscle training on respiratory muscle strength in individuals with Parkinson's disease: Protocol of a randomized clinical trial. PLoS One. 2023;18(9):e0291051. Navas-Garrido I, Martín-Núñez J, Raya-Benítez J, Granados-Santiago M, Navas-Otero A, López-López L, et al. Respiratory Muscle Strength Training in Parkinson's Disease-A Systematic Review and Meta-Analysis. Healthcare. 2025;13(10). van de Wetering-van Dongen VA, Kalf JG, van der Wees PJ, Bloem BR, Nijkrake MJ. The Effects of Respiratory Training in Parkinson's Disease: A Systematic Review. J Parkinsons Dis. 2020;10(4):1315-33. Parkinson’s Foundation. Breathing & respiratory difficulties. Parkinson's Foundation. https://www.parkinson.org/understanding-parkinsons/non-movement-symptoms/breathing. Accessed 28 Jul 2025 Katzel LI, Sorkin JD, Macko RF, Smith B, Ivey FM, Shulman LM. Repeatability of aerobic capacity measurements in Parkinson disease. Med Sci Sports Exerc. 2011;43(12):2381-7. Barbieri RA, Barbieri FA, Zelada-Astudillo N, Moreno VC, Kalva-Filho CA, Zamunér AR. Influence of Aerobic Exercise on Functional Capacity and Maximal Oxygen Uptake in Patients With Parkinson Disease: A Systematic Review and Meta-analysis. Arch Phys Med Rehabil. 2025;106(1):134 − 44. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7255514","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":496744609,"identity":"4d88ef1c-0bcf-4711-8bff-253f9844431c","order_by":0,"name":"Yu-Zhen Chen","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yu-Zhen","middleName":"","lastName":"Chen","suffix":""},{"id":496744610,"identity":"6bf322a0-7372-4874-9355-8b43ba89f4ae","order_by":1,"name":"Qin Zhao","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Qin","middleName":"","lastName":"Zhao","suffix":""},{"id":496744612,"identity":"6cb19222-081d-4e2b-b3c3-7780b885bd6c","order_by":2,"name":"Dan-Mei Lan","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Dan-Mei","middleName":"","lastName":"Lan","suffix":""},{"id":496744615,"identity":"676099c5-1fae-48e6-b0e6-64a7992d093d","order_by":3,"name":"Shuang-Fang Li","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shuang-Fang","middleName":"","lastName":"Li","suffix":""},{"id":496744619,"identity":"3052b436-3efa-485a-93ff-4c2dc1f54da0","order_by":4,"name":"Yue Li","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yue","middleName":"","lastName":"Li","suffix":""},{"id":496744623,"identity":"26814410-4d63-4cea-b797-02adb5ea920d","order_by":5,"name":"Lu Wei","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Lu","middleName":"","lastName":"Wei","suffix":""},{"id":496744625,"identity":"7d5788d8-b74a-4f52-938f-b6cb78facb3b","order_by":6,"name":"Hong Zhang","email":"","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hong","middleName":"","lastName":"Zhang","suffix":""},{"id":496744626,"identity":"4a376ff8-1d99-4625-9f9b-cec41c1ffd76","order_by":7,"name":"Ling-Jing Jin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/ElEQVRIiWNgGAWjYBACPmYgIWHAwMDYzMD4ACQCZDAw8ODRwoakhdngAFFakNkSB2BMvFrYeQ+/sCi4Y9fcznus+kMFiAF04ds2BnlznA7jS7OQMHiW3NjMl3bjwBkQg4HZcG4bg+HOBlxaeMwMJAwOJzM285jdONgGYjCwSfO2MSQYHCBCSwFUC/tvAlqMHwC12IG0MAC12IFsYSZkCzCQDycAtRhLnDkDYjA2S845J2G4AYcWfv4zxp8l/hy2N+w/Y/ihogLEOHzww5syG3lctoAskpZgYEjc2ADhARmMIKYETvVAwPzxAwODvTyUB2eMglEwCkbBKIABAAMgVQjW1xOLAAAAAElFTkSuQmCC","orcid":"","institution":"Shanghai Yangzhi Rehabilitation Hospital, Tongji University","correspondingAuthor":true,"prefix":"","firstName":"Ling-Jing","middleName":"","lastName":"Jin","suffix":""}],"badges":[],"createdAt":"2025-07-30 18:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7255514/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7255514/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88836442,"identity":"986dd38d-186b-47a7-b85d-3a836b9aa9c1","added_by":"auto","created_at":"2025-08-12 01:14:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":15965,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7255514/v1/cd6f5b1605407aeb9e2f9efc.png"},{"id":97900808,"identity":"588ee843-a235-4c08-8553-684898aab8e2","added_by":"auto","created_at":"2025-12-10 15:45:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1126004,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7255514/v1/cc7fa6eb-b511-4fdd-b171-5729170fa15e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Cardiorespiratory Fitness and Pulmonary Function in Parkinson’s Disease: A Cross- Sectional Study with Clinical Correlations","fulltext":[{"header":"Introduction","content":"\u003cp\u003eParkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor dysfunction, though its non-motor manifestations are equally debilitating. Among these, declining cardiorespiratory fitness(CRF)has emerged as a critical yet understudied feature in PD patients[1]. Research indicates that individuals with PD exhibit a 20–30% reduction in peak oxygen uptake (VO₂peak) compared to healthy controls[2], with diminished CRF closely linked to poorer quality of life, cognitive decline, and disease progression[3, 4].Encouragingly, structured aerobic exercise interventions have demonstrated efficacy in enhancing cardiopulmonary function, cognitive performance, and mood regulation in PD patients, potentially slowing disease advancement[5, 6]. Consequently, evidence-based, personalized exercise prescriptions are increasingly recognized as a cornerstone of PD rehabilitation.\u003c/p\u003e\u003cp\u003eCardiopulmonary exercise testing (CPET), the gold standard for assessing CRF, provides critical data to guide individualized exercise regimens[7]. However, implementing CPET in PD populations remains challenging due to motor impairments and autonomic dysfunction[8]. As a result, existing studies predominantly focus on early-stage PD, leaving cardiopulmonary adaptations in moderate-to-advanced disease poorly characterized. Although there is considerable research on pulmonary function (PF) in PD, the interconnectedness of cardiorespiratory function is often overlooked[9]. Most studies focus on isolated assessments of respiratory or exercise-related symptoms with limited exploration of the dynamic relationship between the two[1, 10]. But understanding this relationship is crucial for early identification of high-risk patients and improving clinical outcomes.\u003c/p\u003e\u003cp\u003eThis study integrates pulmonary function testing (PFT) with CPET to systematically compare cardiopulmonary performance and healthy controls, aiming to provide a detailed profile of both respiratory and exercise limitations throughout the disease course and optimize rehabilitative strategies by delineating CRF decline patterns.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eStudy Participants\u003c/p\u003e\u003cp\u003eThis study was designed as a cross-sectional, retrospective research project conducted at the Shanghai Yangzhi Rehabilitation Hospital. A total of 48 patients with PD and 17 healthy controls who visited the hospital between July 2021 and August 2024 were included. Participants in both groups were matched for gender, age, and body mass index (BMI). All participants provided informed consent, and the study protocol was approved by the Ethics Committee of Shanghai Yangzhi Rehabilitation Hospital (Approval Number: MCSC-2025-001). Due to the retrospective nature of the study, informed consent was waived for the use of anonymized, previously collected clinical data, in accordance with ethical standards.\u003c/p\u003e\u003cp\u003eInclusion criteria for the PD group:(1)Diagnosis based on the UK Parkinson's Disease Society Brain Bank Criteria [11], exhibiting progressive motor symptoms (including at least two of the three core symptoms: resting tremor, bradykinesia, and rigidity).༈2༉Ability to comprehend study content and provide informed consent.༈3༉Ability to safely undergo CPET as assessed by a specialist.\u003c/p\u003e\u003cp\u003eExclusion criteria for both groups:(1)Presence of severe cardiovascular or cerebrovascular diseases (e.g., myocardial infarction, unstable angina within the past 3 months, NYHA Class III-IV heart failure).༈2༉Uncontrolled hypertension (systolic blood pressure \u0026gt; 160 mmHg) or diabetes (fasting blood glucose \u0026gt; 10 mmol/L).༈3༉Presence of other neurological disorders (e.g., stroke, dementia, epilepsy).༈4༉Joint diseases affecting motor function or other exercise contraindications (e.g., pulmonary embolism, severe aortic stenosis, malignant arrhythmia).\u003c/p\u003e\u003cp\u003eGeneral Information\u003c/p\u003e\u003cp\u003eThe study collected demographic and health-related variables, including gender, age, education level, BMI, and comorbidities. For the PD group, additional clinical data were recorded, including disease duration and levodopa equivalent daily dose (LEDD)[12]. Disease severity was assessed by a neurologist using the Modified Hoehn-Yahr Staging System[13], a 5-stage scale evaluating the progression of PD symptoms, and the Unified Parkinson’s Disease Rating Scale III (UPDRS-III)[14], which measures the severity of motor symptoms. Activities of daily living were evaluated using the Modified Barthel Index (MBI)[15], and cognitive function was assessed using the Montreal Cognitive Assessment (MoCA)[16], a tool validated for use in the Chinese population[17].\u003c/p\u003e\u003cp\u003eCardiopulmonary Fitness Assessment\u003c/p\u003e\u003cp\u003eAll participants were instructed to refrain from consuming caffeinated beverages (coffee, tea, cola, etc.) for 12 hours prior to testing. To ensure optimal performance during the test, participants took their regular medication one hour before the test to be in an \"on\" state. The CPET was conducted using a specific system with a 12-lead electrocardiogram, blood oxygen saturation monitoring, non-invasive blood pressure measurement, and respiratory gas analysis[18].\u003c/p\u003e\u003cp\u003eThe testing protocol included the following phases[19]:(1)Preparation Phase: Exclusion of contraindications for exercise, collection of medical history, and confirmation of informed consent.༈2༉Baseline Assessment: Static PFT.༈3༉Exercise Testing: Ramp incremental load protocol on a cycle ergometer, with the load adjusted according to individual tolerance. The test phases were:Rest Phase: 3 minutes of baseline heart rate, blood pressure, oxygen saturation, and electrocardiogram data;Warm-up Phase: 3 minutes maintaining a pedal frequency of 55–65 revolutions per minute༛Load Phase: 8–12 minutes of incremental load according to the preset protocol, with continuous physiological monitoring༛Recovery Phase: 3 minutes of post-exercise recovery, assessing fatigue using the Borg Rating of Perceived Exertion (RPE) scale[20].\u003c/p\u003e\u003cp\u003eExercise Termination Criteria\u003c/p\u003e\u003cp\u003eThe exercise test was terminated immediately upon the occurrence of any of the following conditions:(1)Inability to maintain pedaling cadence.༈2༉Symptoms of chest pain, dizziness, visual disturbances, pallor, or cyanosis.༈3༉Abnormal blood pressure (systolic blood pressure \u0026gt; 180 mmHg, diastolic blood pressure \u0026gt; 120 mmHg, or a systolic blood pressure drop \u0026gt; 10 mmHg).༈4༉Electrocardiogram ST segment depression (≥ 0.1 mV horizontal or downsloping or ≥ 0.2 mV upsloping).༈4༉Severe arrhythmias (e.g., frequent premature ventricular contractions, polymorphic ventricular tachycardia, or supraventricular tachycardia)\u003c/p\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eData analysis was performed using SPSS 26.0 software and graphpad prism9. Continuous variables were first tested for normality using the Shapiro-Wilk test. Data with normal distribution were presented as means ± standard deviation, and group comparisons were conducted using independent sample t-tests. Non-normally distributed data were presented as median (interquartile range) and analyzed using the Mann-Whitney U test. Categorical variables were expressed as frequencies (%) and compared using the chi-squared test or Fisher's exact test. Correlation analyses employed Pearson's test for normal data and Spearman's test for non-normal distributions.All statistical tests were two-tailed, and a p-value of \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe study included 48 patients with PD and 17 age-matched controls. No significant differences were observed in baseline demographics or Clinical Characteristics between the two groups. Among PD patients, the median disease duration was 6.50 years (IQR: 4.50\u0026ndash;10.50).The majority of PD participants were classified as H-Y stage 3 (37.5%) or stage 4 (27.1%). The cohort demonstrated moderate motor impairment, with a median UPDRS-III score of 29.5 (IQR: 20.0\u0026ndash;38.0). ( shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic and clinical characteristics of PD patients and controls\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCharacteristics\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePD Group (n\u0026thinsp;=\u0026thinsp;48)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eControlGroup (n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTest Statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDemographics\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge, years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e69.0 (65.0,72.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66.0 (62.0,69.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-1.556ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.120\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e21 (67.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27 (79.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.143ᵇ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.285\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI, kg/m\u0026sup2;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e23.54\u0026thinsp;\u0026plusmn;\u0026thinsp;3.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23.44\u0026thinsp;\u0026plusmn;\u0026thinsp;3.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.107ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.915\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVital signs\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHRrest, bpm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e83.31\u0026thinsp;\u0026plusmn;\u0026thinsp;11.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e83.25\u0026thinsp;\u0026plusmn;\u0026thinsp;11.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.006ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.995\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSBPrest, mmHg\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e124.46\u0026thinsp;\u0026plusmn;\u0026thinsp;14.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e121.53\u0026thinsp;\u0026plusmn;\u0026thinsp;14.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.695ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.489\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDBPrest, mmHg\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e75.79\u0026thinsp;\u0026plusmn;\u0026thinsp;10.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e81.53\u0026thinsp;\u0026plusmn;\u0026thinsp;12.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-1.91ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.061\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComorbidities, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHeart disease\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2 (4.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (17.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.107\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSyncope history\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6 (12.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0 (0.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.327\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHyperlipidemia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10 (20.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (17.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.745\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDiabetes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10 (20.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (17.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.745\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHypertension\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e15 (31.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (17.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.357\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStroke\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4 (8.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (11.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.648\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSmoking history\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4 (8.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (23.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.191\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAlcohol use\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2 (6.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (11.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-ᶜ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.107\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDisease-specific data\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDisease duration, years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e6.50 (4.50,10.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eH-Y stage, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStage 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3 (6.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStage 1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2 (4.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStage 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e9 (18.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStage 2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3 (6.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStage 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e18 (37.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStage 4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13 (27.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUPDRS-III score\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e29.5 (20.0,38.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eAbbreviations: BMI:body mass index; HRrest:resting heart rate; SBP/DBP:systolic/diastolic blood pressure; H-Y :Hoehn \u0026amp; Yahr; UPDRS-III: Unified Parkinson\u0026rsquo;s Disease Rating Scale Part III; Statistical notations: ᵃ Independent samples t-test;ᵇ Pearson's chi-square test;ᶜ Fisher's exact test;ᵈ Mann-Whitney U test (Z-score reported)\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePFT revealed significant impairments in PD patients compared to controls across several parameters. PD patients exhibited markedly reduced forced vital capacity (FVC) (2.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.72 L vs 3.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.86 L, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; 75.46\u0026thinsp;\u0026plusmn;\u0026thinsp;18.91% vs 88.41\u0026thinsp;\u0026plusmn;\u0026thinsp;14.17% predicted, p\u0026thinsp;=\u0026thinsp;0.013) and forced expiratory volume in 1 second (FEV₁) (1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 L vs 2.51\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70 L, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; 73.46\u0026thinsp;\u0026plusmn;\u0026thinsp;18.04% vs 87.76\u0026thinsp;\u0026plusmn;\u0026thinsp;14.53% predicted, p\u0026thinsp;=\u0026thinsp;0.005). The FEV₁/FVC ratio showed a trend towards obstruction in PD patients (median 77.40% vs 81.25%, p\u0026thinsp;=\u0026thinsp;0.059), although this difference did not reach statistical significance.Maximum ventilatory capacity (MVV) was severely compromised in PD patients, with MVV values being approximately 60% of those in controls (51.01\u0026thinsp;\u0026plusmn;\u0026thinsp;22.08% vs 82.67\u0026thinsp;\u0026plusmn;\u0026thinsp;29.34% predicted, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Mid-expiratory flows were significantly reduced at 50% of FVC (MEF₅₀: 2.28 L/s vs 3.92 L/s, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; 63.00% vs 86.50% predicted, p\u0026thinsp;=\u0026thinsp;0.001). However, differences at 25% of FVC (MEF₂₅) were not significant (0.70 L/s vs 1.09 L/s, p\u0026thinsp;=\u0026thinsp;0.236).Measures of diffusion capacity, including Diffusing capacity of the lungs for carbon monoxide(DLCO) (12.74 vs 13.25 mL/min/mmHg, p\u0026thinsp;=\u0026thinsp;0.140) and Diffusing capacity per unit alveolar volume (DLCO/Vₐ )(4.36 vs 5.04 mL/min/mmHg/L, p\u0026thinsp;=\u0026thinsp;0.182), showed no significant differences between the groups, nor did their percent predicted values (all p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). (shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of PFT between PD patients and controls\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable (Unit)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePD Group (n\u0026thinsp;=\u0026thinsp;48)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eControl Group (n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTest Statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFVC (L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-4.055ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFVC (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e75.46\u0026thinsp;\u0026plusmn;\u0026thinsp;18.91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e88.41\u0026thinsp;\u0026plusmn;\u0026thinsp;14.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.563ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.013\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁ (L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.51\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-4.660ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁ (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e73.46\u0026thinsp;\u0026plusmn;\u0026thinsp;18.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e87.76\u0026thinsp;\u0026plusmn;\u0026thinsp;14.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.932ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.005\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁/FVC ratio (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e77.40 (69.30,81.20)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e81.25 (78.40,84.60)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.889ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.059\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁/FVC (% pred.)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e103.00 (92.00,108.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e102.00 (98.00,108.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.705ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.481\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMVV (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e51.01\u0026thinsp;\u0026plusmn;\u0026thinsp;22.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e82.67\u0026thinsp;\u0026plusmn;\u0026thinsp;29.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-4.610ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMEF₅₀ (L/s)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.28 (1.58,2.51)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.92 (2.79,4.46)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-4.143ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMEF₅₀ (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e63.00 (43.00,74.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e86.50 (62.50,104.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-3.399ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMEF₂₅ (L/s)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.70 (0.46,0.83)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.09 (0.88,1.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.185ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.236\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMEF₂₅ (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e58.00 (42.00,73.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72.00 (43.50,86.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.347ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.178\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDLCO (mL/min/mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12.74 (5.65,16.94)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13.25 (10.56,22.63)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.478ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.140\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDLCO (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e56.00 (25.00,68.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47.50 (37.50,79.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.108ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.914\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDLCO/Vₐ (mL/min/mmHg/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.36 (3.65,5.33)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.04 (3.87,5.34)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.333ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.182\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDLCO/Vₐ (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e99.00 (83.00,124.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e106.00 (90.00,117.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.605ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.545\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eAbbreviations: FVC: Forced vital capacity;FEV₁: Forced expiratory volume in 1 second;MVV: Maximum voluntary ventilation;MEF₅₀/FEF₅₀: Maximum expiratory flow at 50% of FVC;MEF₂₅/FEF₂₅: Maximum expiratory flow at 25% of FVC;DLCO: Diffusing capacity of the lungs for carbon monoxide (adjusted for hemoglobin);DLCO/Vₐ: Diffusing capacity per unit alveolar volume;% predicted: Percentage of predicted normal values\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePD patients exhibited significantly lower peak oxygen consumption compared to controls. The median peakVO₂ was 770.00 mL/min in the PD group versus 1066.50 mL/min in the control group (p\u0026thinsp;=\u0026thinsp;0.006), and peak VO₂/kg was also lower in PD patients (13.25 vs 17.10 mL/min/kg, p\u0026thinsp;=\u0026thinsp;0.002). Additionally, PD patients demonstrated reduced peak work capacity (41.50 vs 80.00 watts, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), substantially shorter exercise duration (9.17 vs 16.00 minutes, p\u0026thinsp;=\u0026thinsp;0.004), and lower peak minute ventilation (26.50 vs 41.00 L/min, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).Notably, PD patients exhibited a blunted chronotropic response, with significantly lower peak heart rate (110.50 vs 139.41 bpm, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and a trend toward reduced heart rate at the anaerobic threshold (103.28 vs 113.82 bpm, p\u0026thinsp;=\u0026thinsp;0.065). The respiratory exchange ratio was significantly lower in PD patients (1.02 vs 1.15, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting reduced maximal effort or a ventilatory limitation.Despite achieving lower workloads, PD patients reported higher perceived exertion, with a median Rating of Perceived Exertion (RPE) of 17 versus 15 in controls (p\u0026thinsp;=\u0026thinsp;0.094). Hemodynamic responses also differed between groups, with PD patients showing significantly lower peak systolic blood pressure (160.10 vs 176.88 mmHg, p\u0026thinsp;=\u0026thinsp;0.020).Oxygen pulse and breathing reserve were comparable between groups (both p\u0026thinsp;\u0026gt;\u0026thinsp;0.05), indicating that stroke volume contribution to oxygen delivery and ventilatory capacity relative to demand was preserved in PD patients. (shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of CPET parameters between PD patients and controls\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePD Group (n\u0026thinsp;=\u0026thinsp;48)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eControl Group (n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTest Statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeakVO₂ (mL/min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e770.00 (653.00,1004.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1066.50 (749.00,1317.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.747ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.006\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeakVO₂(% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e58.00 (48.00,67.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e53.50 (49.00,62.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.022ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.982\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeakVO₂/kg (mL/min/kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13.25 (10.45,16.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e17.10 (13.70,19.80)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-3.061ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVO₂atAT (mL/min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e664.50 (549.00,856.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e757.00 (586.00,949.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.502ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.133\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVO₂atAT (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e50.90 (39.75,57.90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e41.55 (38.30,49.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.397ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.162\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVO₂/kgatAT (mL/min/kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e11.40\u0026thinsp;\u0026plusmn;\u0026thinsp;3.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.92\u0026thinsp;\u0026plusmn;\u0026thinsp;3.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.514ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.135\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMETspeak (METs)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4.10 (3.25,4.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e5.10 (4.30,6.20)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-3.219ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMETsat AT (METs)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.562ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.123\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO₂pulse (mL/beat)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7.43\u0026thinsp;\u0026plusmn;\u0026thinsp;2.42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.62\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.239ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.812\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO₂pulse\u003c/p\u003e\u003cp\u003e(% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e77.94\u0026thinsp;\u0026plusmn;\u0026thinsp;15.47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e74.88\u0026thinsp;\u0026plusmn;\u0026thinsp;15.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.671ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.505\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeak VE (L/min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e26.50 (22.50,35.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e41.00 (28.50,47.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-3.483ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBR (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e61.46\u0026thinsp;\u0026plusmn;\u0026thinsp;15.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e58.38\u0026thinsp;\u0026plusmn;\u0026thinsp;19.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.655ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.515\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRER\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-5.089ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHR at AT (bpm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e103.28\u0026thinsp;\u0026plusmn;\u0026thinsp;13.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e113.82\u0026thinsp;\u0026plusmn;\u0026thinsp;20.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.947ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.065\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHRpeak (bpm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e110.50\u0026thinsp;\u0026plusmn;\u0026thinsp;15.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e139.41\u0026thinsp;\u0026plusmn;\u0026thinsp;26.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-4.239ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHRpeak\u003c/p\u003e\u003cp\u003e(% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e75.03\u0026thinsp;\u0026plusmn;\u0026thinsp;10.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e79.82\u0026thinsp;\u0026plusmn;\u0026thinsp;22.49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.156ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.252\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHRR (bpm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e38.15\u0026thinsp;\u0026plusmn;\u0026thinsp;16.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e29.18\u0026thinsp;\u0026plusmn;\u0026thinsp;15.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.956ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.055\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSBPpeak(mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e160.10\u0026thinsp;\u0026plusmn;\u0026thinsp;22.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e176.88\u0026thinsp;\u0026plusmn;\u0026thinsp;30.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.386ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.020\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDBPpeak (mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e79.38\u0026thinsp;\u0026plusmn;\u0026thinsp;12.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e82.29\u0026thinsp;\u0026plusmn;\u0026thinsp;18.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.733ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.466\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExercise duration (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e9.17 (5.27,13.72)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16.00 (7.19,18.88)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.858ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.004\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWR at AT (watt)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e31.00 (16.50,44.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e50.50 (37.50,72.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-3.299ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWRpeak (watt)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e41.50 (25.00,57.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e80.00 (51.50,126.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-3.720ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRPE (Borg Scale)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e17.00 (15.00,17.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e15.00 (13.00,17.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.674ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.094\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDyspnea\u003c/p\u003e\u003cp\u003e(Borg Scale)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5.00 (3.00,7.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e5.00 (2.50,6.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.912ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.360\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eAbbreviations\u003c/em\u003e: \u003cb\u003eVO₂\u003c/b\u003e: \u003cem\u003eOxygen uptake;\u003c/em\u003e\u003cb\u003eAT\u003c/b\u003e: \u003cem\u003eAnaerobic threshold;\u003c/em\u003e\u003cb\u003eMETs\u003c/b\u003e: \u003cem\u003eMetabolic equivalents (1 MET\u0026thinsp;=\u0026thinsp;3.5 mL O₂/kg/min);\u003c/em\u003e\u003cb\u003eO₂ pulse\u003c/b\u003e: \u003cem\u003eOxygen uptake per heart beat (stroke volume \u0026times; arteriovenous O₂ difference);\u003c/em\u003e\u003cb\u003eVE\u003c/b\u003e: \u003cem\u003eMinute ventilation;\u003c/em\u003e\u003cb\u003eBR\u003c/b\u003e: \u003cem\u003eBreathing reserve;\u003c/em\u003e\u003cb\u003eRER\u003c/b\u003e: \u003cem\u003eRespiratory exchange ratio (VCO₂/VO₂);\u003c/em\u003e\u003cb\u003eHR\u003c/b\u003e: \u003cem\u003eHeart rate;\u003c/em\u003e\u003cb\u003eHRR\u003c/b\u003e: \u003cem\u003eHeart rate recovery;\u003c/em\u003e\u003cb\u003eSBP/DBP\u003c/b\u003e: \u003cem\u003eSystolic/diastolic blood pressure;\u003c/em\u003e\u003cb\u003eWR\u003c/b\u003e: \u003cem\u003eWork rate;\u003c/em\u003e\u003cb\u003eRPE\u003c/b\u003e: \u003cem\u003eRating of perceived exertion (Borg Scale 6\u0026ndash;2\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePF parameters demonstrated significant correlations with key CPET variables in patients with PD. FVC and FEV₁ exhibited strong positive associations with peak VO₂(r\u0026thinsp;=\u0026thinsp;0.787 and 0.795, respectively; P\u0026thinsp;\u0026lt;\u0026thinsp;0.01), workload at anaerobic threshold (WR at AT) (r\u0026thinsp;=\u0026thinsp;0.667 and 0.611; P\u0026thinsp;\u0026lt;\u0026thinsp;0.01), and peak workload (WRpeak) (r\u0026thinsp;=\u0026thinsp;0.740 and 0.726; P\u0026thinsp;\u0026lt;\u0026thinsp;0.01).Similarly, maximal voluntary ventilation (MVV) showed moderate correlations with peak VO₂/kg (r\u0026thinsp;=\u0026thinsp;0.554, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01), METs at peak exercise (METspeak) (r\u0026thinsp;=\u0026thinsp;0.583, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01), and peak ventilation (Vepeak) (r\u0026thinsp;=\u0026thinsp;0.505, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01).Notably, percent-predicted values (e.g., FVC% predicted and FEV₁% predicted) displayed divergent patterns. While FEV₁% predicted was positively associated with METs at peak exercise (METspeak) (r\u0026thinsp;=\u0026thinsp;0.520, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01) and systolic blood pressure at peak exercise (SBPpeak) (r\u0026thinsp;=\u0026thinsp;0.364, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), FVC% predicted showed negative correlations with METspeak (r\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.383, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01) and peak VO₂/kg (r\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.356, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).Mid-expiratory flow rates (MEF₅₀, MEF₅₀%) also exhibited significant correlations with exercise capacity metrics (r\u0026thinsp;=\u0026thinsp;0.434\u0026ndash;0.475, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). (shown in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and Fig.\u0026nbsp;1)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCorrelation between PFT and CPET parameters in PD\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"11\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePulmonary Parameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003epeakVO₂\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003epeakVO₂/kg\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMETspeak\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eVEpeak\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eRER\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eHRpeak\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eSBPpeak\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eExercise duration\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003eWR at AT\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003eWRpeak\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFVC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.787\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.515\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.417\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.687\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.025\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.164\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.172\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.511\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.667\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.740\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFVC% pred\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-0.209\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-0.356\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-0.383\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-0.185\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e-0.022\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.293\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.391\u003csup\u003e**P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-0.280\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.094\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.062\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.795\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.586\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.533\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.675\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.361\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.220\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.240\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.502\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.611\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.726\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁% pred\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.360\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.462\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.520\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.318\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.198\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.300\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.364\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.368\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.144\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.185\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMVV\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.501\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.554\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.583\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.505\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.264\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.474\u003csup\u003e**P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.304\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.341\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.384\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.423\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMEF50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.465\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.354\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.434\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.389\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.264\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.474\u003csup\u003e**P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.304\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-0.203\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.269\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.333\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMEF50\u003c/p\u003e\u003cp\u003e(% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.422\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.403\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.475\u003csup\u003e**S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.373\u003csup\u003e*S\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.356\u003csup\u003e*P\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.234\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.288\u003csup\u003eP\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.228\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.220\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0.286\u003csup\u003eS\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"11\"\u003e\u003cem\u003eAbbreviations: **P\u0026thinsp;\u0026lt;\u0026thinsp;0.01; *P\u0026thinsp;\u0026lt;\u0026thinsp;0.05; P\u0026thinsp;=\u0026thinsp;Pearson's correlation ;S\u0026thinsp;=\u0026thinsp;Spearman's rank correlation\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe assessment of PF and exercise capacity in our PD cohort revealed significant impairment patterns. This disparity between relatively preserved PF (84% of patients with FEV₁ \u0026ge;50% predicted) and markedly impaired exercise capacity (96% with peakVO₂ \u0026lt;20 mL/kg/min) suggests that factors beyond pulmonary limitation contribute significantly to reduced exercise tolerance in PD. (shown in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDistribution of PF and exercise capacity severity in PD patients\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSeverity Category\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFrequency (n)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePercentage (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFEV₁ (% predicted)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;80% (normal)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e43.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50\u0026ndash;80% (moderate)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e41.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;50% (severe)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e14.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTotal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e100.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003epeakVO₂ (mL/kg/min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;20 (normal)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e4.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15\u0026ndash;20 (mild)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e29.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;15 (severe)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e66.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTotal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e100.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePatients with higher aerobic capacity (VO₂peak\u0026thinsp;\u0026ge;\u0026thinsp;15 mL/kg/min, n\u0026thinsp;=\u0026thinsp;16) were more likely to be male (68.8% vs. 31.3%, p\u0026thinsp;=\u0026thinsp;0.014) and had better cognitive function (MoCA: 27.0 vs. 22.0, p\u0026thinsp;=\u0026thinsp;0.007) and daily living scores (MBI: 94.0 vs. 78.5, p\u0026thinsp;=\u0026thinsp;0.020) compared to those with VO₂peak\u0026thinsp;\u0026lt;\u0026thinsp;15 (n\u0026thinsp;=\u0026thinsp;32). The low aerobic capacity group had higher H\u0026amp;Y stage (p\u0026thinsp;=\u0026thinsp;0.044), suggesting greater disease severity. No significant differences were found in age, BMI, disease duration, UPDRS-III, or cardiovascular measures (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). ( shown in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical characteristics by aerobic capacity groups (VO₂peak\u0026thinsp;\u0026ge;\u0026thinsp;15 vs\u0026thinsp;\u0026lt;\u0026thinsp;15 mL/kg/min)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCharacteristic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eVO₂peak\u0026thinsp;\u0026ge;\u0026thinsp;15 (n\u0026thinsp;=\u0026thinsp;16)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eVO₂peak\u0026thinsp;\u0026lt;\u0026thinsp;15 (n\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTest Statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDemographics\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e11 (68.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10 (31.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.095ᵇ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.014*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e65.1\u0026thinsp;\u0026plusmn;\u0026thinsp;8.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e68.8\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.853ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.070\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e23.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e23.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.823ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.414\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eClinical Measures\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDisease duration (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5.0 (5.0-11.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7.0 (4.5-9.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.040ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.969\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eH\u0026amp;Y stage\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.0 (2.0\u0026ndash;3.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.0 (2.3-4.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.017ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.044*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUPDRS-III\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e24.0 (20.0-36.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e32.0 (21.5\u0026ndash;39.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.106ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.269\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFunctional Scores\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMoCA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e27.0 (24.0\u0026ndash;28.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e22.0 (19.0\u0026ndash;26.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.679ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.007**\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMBI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e94.0 (82.0\u0026ndash;95.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e78.5 (65.0\u0026ndash;93.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-2.333ᵈ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.020*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePhysiological Parameters\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHRrest (bpm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e84.7\u0026thinsp;\u0026plusmn;\u0026thinsp;12.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e82.6\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.600ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.551\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSBPrest (mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e121.1\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e126.1\u0026thinsp;\u0026plusmn;\u0026thinsp;16.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-1.094ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.280\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDBPrest (mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e74.9\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e76.2\u0026thinsp;\u0026plusmn;\u0026thinsp;10.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-0.414ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.681\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLEDD (mg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e571.6\u0026thinsp;\u0026plusmn;\u0026thinsp;300.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e567.3\u0026thinsp;\u0026plusmn;\u0026thinsp;297.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.048ᵃ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.962\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eAbbreviations:MoCA: Montreal Cognitive AssessmentMBI: Modified Barthel Index (activities of daily living)LEDD: Levodopa equivalent daily dose\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discusion","content":"\u003cp\u003eThis study aimed to investigate the relationship between PTF, CRF, and clinical outcomes in patients with PD. Our findings reveal that PD patients exhibit significant deficits in both pulmonary ventilation function and aerobic capacity compared to healthy controls. These deficits are closely related to clinical symptoms, disease progression, and quality of life, suggesting that the decline in cardiopulmonary function plays a important role in the non-motor manifestations of PD.\u003c/p\u003e\u003cp\u003eOur study demonstrated significant impairments in static PF in PD patients compared to healthy controls, including reduced FVC, FEV₁, and MVV, along with decreased MEF50. These findings suggest a mixed pattern of restrictive and obstructive ventilatory dysfunction in PD.The observed restrictive pattern (evidenced by reduced FVC and FEV₁ with preserved FEV₁/FVC ratio) may be attributed to thoracic rigidity, postural abnormalities (e.g., kyphosis), and respiratory muscle weakness, as previously reported in PD patients[21]. Additionally, the obstructive component (reflected by significantly lower MEF₅₀) could stem from peripheral airway obstruction due to oropharyngeal muscle dysfunction, autonomic dysregulation, or upper airway collapse[22]. Notably, while the FEV₁/FVC ratio did not reach statistical significance, the trend toward reduction aligns with studies highlighting heterogeneous airway involvement in PD.The marked decline in MVV further underscores the combined impact of respiratory muscle fatigue and reduced lung compliance, potentially exacerbating dyspnea and exercise intolerance in this population[22].\u003c/p\u003e\u003cp\u003eCPET further confirmed the severity of these impairments, with PD patients exhibiting significantly lower CRF, as well as an earlier onset of anaerobic threshold (AT). These results reflect a marked impairment in aerobic metabolism and align with findings, which reported a 30% reduction in VO₂peak in PD patients compared to healthy individuals, indicating limited cardiopulmonary adaptation during high-intensity exercise[18, 23]. Additionally, a delayed physiological response during exercise was observed, as evidenced by reduced peak heart rate, peak ventilation, and respiratory exchange ratio (RER) in PD patients, consistent with the results of Kanegusuku et al[24].\u003c/p\u003e\u003cp\u003eIn addition to these findings, we performed correlation analyses between static PF and CPET parameters. These correlations suggest that PF plays a crucial role in exercise performance, with better lung function linked to higher levels of exercise capacity. Respiratory muscle training (RMT) has been shown to significantly improve aerobic capacity in PD. High-intensity RMT, involving daily training of both inspiratory and expiratory muscles, enhances maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), improving endurance, dyspnea, fatigue, and quality of life. These improvements indicate that respiratory muscle function is closely related to better exercise capacity, particularly for aerobic activities [25].Systematic reviews and meta-analyses confirm that RMT improves respiratory function markers like peak expiratory flow rate (PEFR), which directly impacts physical performance. While MIP improvements are less pronounced, RMT's overall positive effects on exercise capacity are evident [26]. Additionally, inspiratory muscle training (IMT) has been shown to improve upper limb function and reduce fatigue, further supporting its value in PD treatment [27].The Parkinson's Foundation also recommends deep breathing exercises to enhance lung function and aerobic capacity in PD patients, reinforcing the importance of integrating these exercises into rehabilitation programs[28].\u003c/p\u003e\u003cp\u003eOur study further analyzed the clinical correlation between CRF and PTF results, revealing that despite moderate levels of lung function preservation, 96% of PD patients exhibited severe limitations in aerobic endurance. This phenomenon suggests that exercise intolerance is not solely attributable to pulmonary restriction, but is also significantly influenced by various \"extrathoracic mechanisms.\" First, autonomic dysfunction, a common non-motor feature in PD, affects key physiological processes during exercise, including heart rate, blood pressure, and ventilation responses. We observed that PD patients had significantly lower peak heart rate (HRpeak), peak systolic blood pressure (SBPpeak), and RER compared to controls, reflecting limited sympathetic activation[18]. The absence of appropriate cardiovascular responses during exercise severely impairs oxygen delivery efficiency, leading to early fatigue and premature cessation of physical activity. Additionally, peripheral muscle metabolic dysfunction and impaired oxygen utilization further limit the exercise capacity in PD patients. Mitochondrial dysfunction, decreased capillary density, and muscle mass loss in PD contribute to a reduced ability of skeletal muscles to uptake and utilize oxygen (a-v O₂ difference), limiting VO₂peak even when pulmonary oxygen supply is adequate[29]. Furthermore, postural abnormalities (such as forward neck flexion and thoracic posture) restrict chest expansion, and muscle rigidity reduces the flexibility of respiratory muscles, leading to increased perceived exertion (RPE) even under lower exercise loads. It is also noteworthy that psychological and cognitive factors play a significant role in these extrathoracic mechanisms. Our study found that patients with higher VO₂peak performed better in MoCA and MBI scores, indicating that cognitive function and activities of daily living are closely linked to exercise endurance. PD is often accompanied by depression, apathy, and executive dysfunction, which may reduce motivation and subjective effort levels, leading patients to experience fatigue before reaching their physiological limits, thus limiting their actual exercise performance.\u003c/p\u003e\u003cp\u003eThis study also found that, despite some differences in clinical indicators such as disease duration and UPDRS-III scores in PD patients, these factors did not show significant correlations with changes in cardiopulmonary function. This finding is consistent with the results of Wang et al. (2024), who reported that the decline in cardiopulmonary function in PD patients occurs universally, regardless of the disease duration, and is not solely dependent on clinical staging or medication. Furthermore, good CRF appears to have a positive impact on the cognitive function and daily living abilities of PD patients. Our study found that patients with a VO₂peak greater than 15 mL/kg/min scored better on cognitive function (MoCA score) and daily living abilities (MBI score) than those with a VO₂peak less than 15 mL/kg/min. Research by Schenkman et al [5]in their study on the effects of high-intensity aerobic exercise intervention in PD patients showed similar findings, indicating that improving CRF can effectively improve both cognitive and functional status in PD patients.\u003c/p\u003e\u003cp\u003eBased on these findings, the decline in cardiopulmonary fitness in PD patients is a result of multiple synergistic factors, highlighting the central role of individualized exercise prescriptions in PD rehabilitation. Traditional pulmonary function assessments are insufficient to fully reflect the functional status of PD patients. Therefore, we recommend the widespread use of CPET in clinical practice to identify limiting factors and develop personalized exercise prescriptions. Additionally, interventions such as autonomic nervous system training, RMT, resistance training, and psychological rehabilitation can help break the vicious cycle of \"exercise function limitation\u0026mdash;decline in physical capacity,\" improving cardiopulmonary health and quality of life. Compared to traditional standardized programs, personalized interventions based on CRF assessment can more accurately match the patient\u0026rsquo;s physiological status and disease characteristics, significantly improving VO₂peak and exercise endurance. For patients with poor exercise function, low-intensity aerobic training combined with RMT can be used, while for those with better exercise function, the intensity can be gradually increased to further improve CRF and help delay disease progression[30]. However, our study has some limitations. Its cross-sectional design precludes causal inference, and the applicability of CPET may be limited in advanced PD stages. Future longitudinal studies should focus on the progression of central pulmonary dysfunction in PD and evaluate the long-term effects of exercise interventions on CRF and disease progression.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eOur study demonstrates that PD patients experience significant declines in both PF and CRF, which are associated with worse clinical and functional outcomes. The observed dissociation between preserved pulmonary function and impaired CRF suggests that exercise intolerance in PD is primarily driven by factors beyond pulmonary limitations, such as neuromuscular dysfunction and autonomic imbalance. Integrating CRF assessments into clinical practice and developing individualized rehabilitation programs can help break the \"motor dysfunction-cardiopulmonary decline\" vicious cycle and provide more comprehensive treatment options for PD patients. Future research should further explore how targeted exercise interventions can improve CRF and optimize clinical outcomes for PD patients.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePD\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eParkinson's Disease\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCRF\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCardiorespiratory Fitness\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePF\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePulmonary Function\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePFT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePulmonary Function Testing\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCPET\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCardiopulmonary Exercise Testing\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eVO₂peak\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePeak Oxygen Uptake\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMETs\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMetabolic Equivalents (1 MET\u0026thinsp;=\u0026thinsp;3.5 mL O₂/kg/min)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHRrest\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eResting Heart Rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eSBP\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eSystolic Blood Pressure\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eDBP\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eDiastolic Blood Pressure\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFVC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eForced Vital Capacity\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFEV₁\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eForced Expiratory Volume in 1 second\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMVV\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMaximum Voluntary Ventilation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMEF₅₀\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMaximum Expiratory Flow at 50% of FVC\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMEF₂₅\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMaximum Expiratory Flow at 25% of FVC\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eDLCO\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eDiffusing Capacity of the Lungs for Carbon Monoxide\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eDLCO/Vₐ\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eDiffusing Capacity per Unit Alveolar Volume\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRPE\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRating of Perceived Exertion (Borg Scale)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHRpeak\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePeak Heart Rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eWR\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eWork Rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eAT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAnaerobic Threshold\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eBPM\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBeats Per Minute\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMBI\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eModified Barthel Index (Activities of Daily Living)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eMoCA\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMontreal Cognitive Assessment\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eLEDD\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eLevodopa Equivalent Daily Dose\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eH-Y\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHoehn \u0026amp; Yahr\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eUPDRS-III\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eUnified Parkinson\u0026rsquo;s Disease Rating Scale Part III\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eBMI\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBody Mass Index\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRER\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eRespiratory Exchange Ratio\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eVE\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eMinute Ventilation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eBR\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBreathing Reserve\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHRR\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHeart Rate Recovery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eDLCO/Vₐ (% predicted)\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePercentage of Predicted Diffusing Capacity per Unit Alveolar Volume\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFVC (% predicted)\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePercentage of Predicted Forced Vital Capacity\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFEV₁ (% predicted)\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePercentage of Predicted Forced Expiratory Volume in 1 second\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eDLCO\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eDiffusing Capacity of the Lungs for Carbon Monoxide (adjusted for hemoglobin)\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eWRpeak\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePeak Work Rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eVO₂ at AT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eOxygen Uptake at Anaerobic Threshold\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eVO₂/kg at AT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eOxygen Uptake per Kilogram at Anaerobic Threshold\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePEFR\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePeak Expiratory Flow Rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eThis retrospective cross-sectional study was conducted in accordance with the ethical standards of the institutional research committee and the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Ethical approval was waived by the Medical Ethics Committee of Shanghai Yangzhi Rehabilitation Hospital due to the retrospective nature of the study (Approval Number: MCSC-2025-001). As this study used anonymized, previously collected clinical data, the requirement for informed consent was also waived by the same committee.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author (\u003cstrong\u003eYu-Zhen Chen\u003c/strong\u003e) upon reasonable request and subject to a signed data access agreement. Requests can be made via institutional email.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was supported by the National Key Clinical Specialty Discipline Construction Project of China (Z155080000004), the Shanghai Research Center of Rehabilitation Medicine \u0026ndash; Top Priority Research Center of Shanghai (2023ZZ02027), the Shanghai Clinical Research Ward Project (SHDC2023CRW018B), the Shanghai Hospital Development Center Foundation \u0026ndash; Shanghai Municipal Hospital Rehabilitation Medicine Specialty Alliance (SHDC22023304),the\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eShanghai Yangzhi Rehabilitation Hospital(2024QNRC14),.and the Shanghai Yangzhi Rehabilitation Hospital(2023QNRC11).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eYu-Zhen Chen and Qin Zhao co-first authors and contributed equally to this work.\u003c/p\u003e\n\u003cp\u003eGuarantor of integrity of the entire study: Yu-Zhen Chen, Qin Zhao. Study concepts: Yu-Zhen Chen, Qin Zhao. Study design: Yu-Zhen Chen，Ling-Jing Jin .Data acquisition: Yu-Zhen Chen, Lu Wei, Shuang-Fang Li, Hong Zhang，Yue Li. Data analysis: Yu-Zhen Chen，Dan-Mei Lan. Manuscript preparation: Yu-Zhen Chen. Manuscript editing: Yu-Zhen Chen, Qin Zhao. Manuscript review: Qin Zhao, Ling-Jing Jin.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDepartment of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital, Shanghai, 201619, China;Yu-Zhen Chen\u0026nbsp;\u0026amp;\u0026nbsp; Dan-Mei Lan,\u0026nbsp;\u0026amp;\u0026nbsp;Yue Li,\u0026amp;\u0026nbsp;Lu Wei \u0026amp;\u0026nbsp;Shuang-Fang Li \u0026amp;\u0026nbsp;Hong Zhang;\u003c/p\u003e\n\u003cp\u003eDepartment of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital, School of Medicine, Tongji University, Shanghai, 201619, China.;Qin Zhao \u0026amp; Ling-Jing Jin\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePechstein AE, Gollie JM, Guccione AA. 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Mov Disord. 1994;9(1):76\u0026ndash;83.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShah S, Vanclay F, Cooper B. Improving the sensitivity of the Barthel Index for stroke rehabilitation. J Clin Epidemiol. 1989;42(8):703-9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXu Q, Zhou M, Jiang C, Wu L, He Q, Zhao L, et al. Application of the Chinese Version of the Montreal Cognitive Assessment-Basic for Assessing Mild Cognitive Impairment in Parkinson's Disease. Brain Sci. 2021;11(12).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNational Institute for Health and Care Excellence. Parkinson's disease in adults: diagnosis and management. London: National Institute for Health and Care Excellence (NICE); 2017.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang K, Cheng H, Yang B, Liu D, Maria M, Wu Q, et al. Assessment of cardiorespiratory fitness in Chinese patients with early to mid-stage Parkinson's disease. Int J Neurosci. 2024:1\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGuazzi M, Arena R, Halle M, Piepoli MF, Myers J, Lavie CJ. 2016 Focused Update: Clinical Recommendations for Cardiopulmonary Exercise Testing Data Assessment in Specific Patient Populations. Circulation. 2016;133(24):e694-711.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDing W, You T, Gona PN, Milliken LA. Validity and reliability of a Chinese rating of perceived exertion scale in young Mandarin speaking adults. Sports Med Health Sci. 2020;2(3):153-8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDe Pandis MF, Starace A, Stefanelli F, Marruzzo P, Meoli I, De Simone G, et al. Modification of respiratory function parameters in patients with severe Parkinson's disease. Neurol Sci. 2002;23 Suppl 2:S69-70.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHammer MJ, Barlow SM. Laryngeal somatosensory deficits in Parkinson's disease: implications for speech respiratory and phonatory control. Exp Brain Res. 2010;201(3):401-9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSpeelman AD, Groothuis JT, van Nimwegen M, van der Scheer ES, Borm GF, Bloem BR, et al. Cardiovascular responses during a submaximal exercise test in patients with Parkinson's disease. J Parkinsons Dis. 2012;2(3):241-7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKanegusuku H, Cucato GG, Longano P, Okamoto E, Piemonte MEP, Correia MA, et al. Acute Cardiovascular Responses to Self-selected Intensity Exercise in Parkinson's Disease. Int J Sports Med. 2022;43(2):177\u0026thinsp;\u0026minus;\u0026thinsp;82.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBrito SAF, Scianni AA, Silveira BMF, Oliveira ERM, Mateus ME, Faria C. 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Parkinson's Foundation. https://www.parkinson.org/understanding-parkinsons/non-movement-symptoms/breathing. Accessed 28 Jul 2025\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKatzel LI, Sorkin JD, Macko RF, Smith B, Ivey FM, Shulman LM. Repeatability of aerobic capacity measurements in Parkinson disease. Med Sci Sports Exerc. 2011;43(12):2381-7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBarbieri RA, Barbieri FA, Zelada-Astudillo N, Moreno VC, Kalva-Filho CA, Zamun\u0026eacute;r AR. Influence of Aerobic Exercise on Functional Capacity and Maximal Oxygen Uptake in Patients With Parkinson Disease: A Systematic Review and Meta-analysis. Arch Phys Med Rehabil. 2025;106(1):134\u0026thinsp;\u0026minus;\u0026thinsp;44.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Parkinson’s disease, Cardiorespiratory fitness, Cardiopulmonary exercise testing, Pulmonary function, Pulmonary function testing","lastPublishedDoi":"10.21203/rs.3.rs-7255514/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7255514/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eParkinson’s disease (PD) is frequently accompanied by impairments in cardiorespiratory fitness (CRF) and pulmonary function (PF), which may diminish quality of life and limit functional independence. This study aimed to assess CRF and PF in patients with PD and explore their interrelationship.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis cross-sectional study enrolled 48 patients with PD (Hoehn-Yahr stage 1–4) and 17 age-matched healthy controls. All participants underwent comprehensive assessments, including pulmonary function testing (PFT) and cardiopulmonary exercise testing(CPET), alongside the systematic collection of demographic and clinical characteristics. PD patients were additionally evaluated for motor symptoms using the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III), disease severity (Hoehn-Yahr stage, H-Y stage), cognitive function (Montreal Cognitive Assessment, MoCA), and activities of daily living (Modified Barthel Index, MBI). Correlation analyses were conducted to investigate the relationship between PFT and CPET outcomes, with a focus on identifying potential associations between respiratory impairment and exercise capacity in PD.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCompared to controls, PD patients demonstrated significantly reduced PF and markedly impaired exercise capacity. Although 84% of PD patients showed preserved PF, 96% exhibited severe reductions in CRF. Strong correlations were observed between pulmonary measures and exercise capacity. Higher CRF levels were associated with better cognitive function and greater independence in daily activities. Disease severity was inversely related to CRF.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePD patients experience significant declines in both PF and CRF, which are linked to worse clinical and functional outcomes. The discordance between preserved PF and severely reduced CRF suggests that non-pulmonary mechanisms may contribute to exercise intolerance. CPET should be integrated into PD assessments to guide personalized rehabilitation strategies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration: \u003c/strong\u003eNot applicable.\u003c/p\u003e","manuscriptTitle":"Cardiorespiratory Fitness and Pulmonary Function in Parkinson’s Disease: A Cross- Sectional Study with Clinical Correlations","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-12 01:14:29","doi":"10.21203/rs.3.rs-7255514/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"32a4e419-0289-4e9d-9fe4-b937b64bb646","owner":[],"postedDate":"August 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-10T11:09:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-12 01:14:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7255514","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7255514","identity":"rs-7255514","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}