Monitoring muscle oxygen saturation during forest trail hiking: A randomized controlled trial of physiological and immunological observations in older adults

Monitoring muscle oxygen saturation during forest trail hiking: A randomized controlled trial of physiological and immunological observations in older adults | 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 Article Monitoring muscle oxygen saturation during forest trail hiking: A randomized controlled trial of physiological and immunological observations in older adults Sang-Geun Jo, Dong-Hyun Yoo, Yong-Seok Jee This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7779628/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Apr, 2026 Read the published version in Scientific Reports → Version 1 posted 4 You are reading this latest preprint version Abstract Forest-based physical activity (PA) has been proposed as a strategy to counteract age-associated declines in health, yet its mechanistic underpinnings remain unclear. Muscle oxygen saturation (SmO₂) may serve as a real-time marker of physiological adaptation during PA. We conducted a 12-week randomized controlled trial in 69 older adults (aged 66–78 years), comparing forest trail hiking (FTH, n = 34) with a control group (CON, n = 35). Participants in the FTH engaged in progressive low- to high-intensity hiking (120 min, twice weekly). SmO₂ of the vastus lateralis was continuously monitored, and pre- and post-intervention assessments included body composition, cardiopulmonary performance, and immunological markers. During hiking, SmO₂ declined progressively, reaching a nadir at 60–90 min before partial recovery. After 12 weeks, the FTH group showed reduced body fat, increased muscle mass, and improved VO₂max, FVC, FEV₁, and PEF, whereas the CON group exhibited adverse trends. Immunological changes included decreased IL-6 and increased IL-10 and IL-12 in the FTH, alongside enhanced lymphocyte subsets. Ultimately, continuous SmO₂ monitoring provides an informative marker of muscle oxygen dynamics during prolonged outdoor activity. Forest trail hiking elicited broad physiological and immunological benefits in older adults, underscoring its therapeutic potential for healthy ageing. Trial registration This study was retrospectively registered with the Clinical Research Information Service of the Korea Centers for Disease Control and Prevention under Clinical Trials KCT0008712 on 18/08/2023. Health sciences/Diseases Health sciences/Health care Health sciences/Medical research Biological sciences/Physiology Forest trail hiking Older adults Skeletal muscle oxygen saturation Immunity Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction South Korea is experiencing one of the world’s most rapid demographic transitions, with adults aged ≥ 65 years already comprising nearly one-fifth of the population and projected to exceed 40% by 2050. Although life expectancy continues to rise, ageing is accompanied by increased medical costs, reduced life satisfaction, and progressive functional decline 1 . Central to this decline is sarcopenia, the age-related loss of muscle mass and strength 2 , which not only impairs mobility but also compromises respiratory muscles essential for cardiopulmonary function 3 . Accumulation of adipose tissue has been shown to exacerbate systemic inflammation through increased release of pro-inflammatory cytokines, notably interleukin (IL)-6, while simultaneously impairing the cytotoxic activity of natural killer (NK) cells and the functional competence of T lymphocytes. These immuno-metabolic disturbances are considered key mechanisms that accelerate senescence, compromise physiological resilience, and ultimately worsen survival outcomes 4,5 . Regular engagement in physical activity (PA) not only mitigates the onset of sarcopenia and preserves cardiopulmonary function but also exerts beneficial immunomodulatory effects by enhancing anti-inflammatory mediators, such as IL-10 or IL-12, and promoting the activity of critical innate and adaptive immune cell populations 6,7 . In the context of PA-induced muscle metabolism, myokines serve as pivotal mediators by promoting immunocyte functionality, attenuating adipose tissue accumulation, and mitigating oxidative stress–related damage. Walking has been reported to enhance skeletal muscle metabolism, promote immune homeostasis, and upregulate anti-inflammatory mediators 2,8 . Phytoncides released from forests are also known to reduce inflammation and enhance immunocytes activity, suggesting that performing the aforementioned walking in a forest environment may provide additional benefits for older adults 9 . Forest hiking refers to a form of PA performed along designated walking or trekking paths within forest environments, incorporating varying slopes and terrains 10 . Forest-based activities, often referred to as "forest healing", have been shown to lower stress hormone, improve mood, and enhance immunocytes, through the inhalation of phytoncides released by trees 11,12 . This concept encompasses restorative interventions carried out in forest mountain, utilizing the unique physical and environmental characteristics of forests to support health recovery and improvement 13,14 . While forest trail hiking may offer substantially greater benefits for older adults compared with walking in general environments 15 , it nevertheless presents certain drawbacks. In other words, the physiological monitoring of older adults during forest-based activity remains challenging, particularly on ever-changing trails where oxygen delivery and utilization are difficult to assess 16,17 . Near-infrared spectroscopy (NIRS) is a non-invasive technique capable of providing functional insights into skeletal muscle oxidative metabolism during PA in both healthy individuals and clinical populations. When applied to forest trail settings, NIRS may help minimize research limitations and enable the assessment of exercise performance and tolerance in older adults 17,18 , thereby offering valuable evidence for evaluating the feasibility of forest trail interventions in this population. In other words, the use of NIRS to measure skeletal muscle oxygen saturation (SmO₂) holds potential for assessing muscle oxygen utilization not only in outdoor environments but also during forest trail hiking across varying slopes and terrains; however, research on its application under such conditions remains absent. Here, we report a randomized controlled trial designed to (i) characterize SmO₂ dynamics during forest trail hiking in older adults and (ii) evaluate the long-term effects of a 12-week program on body composition, cardiopulmonary function, and immune regulation. This integrated approach may address a critical gap in understanding how sustained, ecologically valid PA influences physiological and immunological ageing. Methodology Study design and participants We conducted a prospective, double-blind, randomized controlled trial in community-dwelling older adults residing in two senior living facilities in Seoul, Korea (May–August 2025). All procedures were conducted in accordance with the Declaration of Helsinki. The study was approved by the Hanseo University Ethics Committee (HS23-08-02) and registered with the Clinical Research Information Service (KCT0008712). All participants provided written informed consent. Eligible participants were aged 66–78 years, nonsmokers, free from major cardiopulmonary, metabolic, or psychiatric disorders, and had not engaged in regular PA within six months. Participants were excluded if they had previously undergone weight reduction therapies, were currently taking medications that could influence body composition, or had undergone surgery within the past year. Individuals with a documented history of cardiovascular or cerebrovascular disease, malignancy, or psychiatric disorders were also excluded. Sample size estimation was performed using G*Power software (version 3.1.9.7; Heinrich-Heine-Universität, Düsseldorf, Germany) with the following parameters: effect size f(V) = 0.25, α error probability = 0.05, power (1–β) = 0.95, number of groups = 2 (experimental vs. control), and number of measurements = 2 (pre- and post-intervention). The calculation indicated that a minimum of 54 was required 19 . To account for an anticipated dropout rate of 20% 20 , additional participants were recruited. As shown in Fig. 1, a total of 87 individuals were initially recruited from two separate facilities to minimize the possibility of cross-group communication. Thirteen participants were excluded either due to failure to meet the inclusion criteria or for personal reasons, leaving 74 participants who completed surveys and baseline assessments. Random allocation was conducted using a tag selection performed by two independent representatives. One facility was assigned to the control group (CON) and the other to the forest trail hiking group (FTH), each consisting of 37 participants at baseline. During the 12-week intervention, two participants in the CON were excluded due to incomplete SmO₂ measurements or missing data, resulting in 35 participants for the final analysis. In the FTH, two participants withdrew, and one dataset was missing, leaving 34 participants for analysis. Intervention Forest trail hiking was conducted in the Osaek area of Seoraksan National Park, South Korea. Based on previously published studies 21,22 , a hiking course was selected to ensure a low-to-moderate-to-high intensity level for older adults’ physical capacities. Before beginning the hike, participants in the FTH performed stretching exercises for 10–15 min, progressing from a seated to a standing position. Upon completion of the hiking session, they returned indoors and conducted another 10–15 min of stretching, transitioning from a seated to a supine position. The intervention was carried out over 12 weeks, with two sessions per week (Tuesdays and Fridays). As shown in Fig. 2, participants were instructed to complete a round-trip hike from the starting point to the designated return point within a target duration of 120 min. The hiking program was designed to achieve an exercise intensity corresponding to 40–80% of each participant’s maximal oxygen uptake (VO₂max), as determined through a pre-intervention treadmill-based cardiopulmonary exercise testing. To ensure that this target intensity was maintained, each participant’s individualized heart rate range was programmed into a smartwatch provided for use during the intervention. Additionally, the rating of perceived exertion 10-point scale was employed at 10- to 20-min intervals to monitor subjective effort levels 23 . If a participant's exertion exceeded the equivalent of 81% VO₂max, a rest period of 3 min was implemented. These rest periods were not counted toward the total 120-min hiking duration goal. Outcome m easures Baseline characteristics Demographic variables included living arrangement (1 = living alone; 2 = living with spouse or family) and self-reported economic status (1 = very poor; 2 = poor; 3 = average; 4 = well-off). Physician-diagnosed chronic conditions were recorded as multiple responses and included: none, osteoporosis, overweight, obesity, otorhinolaryngologic disease, endocrine disease, urological disease, dyslipidaemia, liver disease, spinal deformity, hypertension, diabetes, gastrointestinal disease, and arthritis. Social activity level was rated on a five-point scale (1 = very good; 5 = very poor). Cardiovascular and respiratory symptoms were coded as present (1) or absent (0) for the following: family history of premature heart surgery or sudden cardiac death, smoking within the past 6 months, chest pain or discomfort, dizziness or syncope, dyspnoea while sitting or lying down, ankle edema unrelated to prolonged standing, palpitations, intermittent claudication, history of heart murmur, and shortness of breath or unusual fatigue during normal activity 24 . Daily sleep duration was recorded by noting the time of falling asleep and calculating the interval until waking the following morning and commencing routine daily activities, which was then defined as the "sleep duration." Daily caloric intake was assessed using meal plans designed by a registered dietitian. A single researcher entered the dietary data into the CAN-Pro 5.0 program (http://canpro5.kns.or.kr; Korean Nutrition Society) to record and analyze the daily intake of all participants. Daily PA levels were estimated using the International PA Questionnaire–Short Form 25,26 . Sleep duration, daily caloric intake, and PA levels were recorded daily from the beginning to the end of the intervention. These data were aggregated on a monthly basis and averaged for comparative analysis between the pre- and post-intervention periods. Muscle oxygen saturation measure The study measured SmO₂ using a near-infrared spectroscopy device, the Moxy Monitor (Muscle Oxygen Monitor, Fortiori Design LLC, Hutchinson, MN, USA). Measurements are taken at four distinct wavelengths, resulting in eight individual readings per cycle. The default sampling rate cycles through these wavelengths 80 times every 2 sec, producing an output frequency of 0.5 Hz 27 . During the forest trail hiking sessions, the sensor was attached to the vastus lateralis (VL) using hypoallergenic, low-adhesive patches designed to be gentle on sensitive skin. To ensure stability at the attachment site without applying excessive pressure to the muscle, the sensor was further secured using a fixation strap. Primary outcomes All primary outcomes were assessed at 7:00 a.m., the scheduled wake-up time, with participants reporting to the designated testing area in a predetermined sequence. Body composition All participants had their height and body composition measured using an InBody 720 (Biospace Co., Ltd., Seoul, Korea) while wearing light clothing and no metallic accessories, after voiding 30 min prior. Standing on the device’s platform and holding the handles for 3 min, measurements of height, body weight, muscle mass, fat mass, and body mass index were obtained. This bioelectrical impedance analysis method has been reported to show a high correlation with dual-energy X-ray absorptiometry 28 . Cardiopulmonary function Pulmonary function was assessed using a metabolic analyzer (Quark CPET ® , Omnia software, version 1.6.7, Cosmed, Rome, Italy). All participants were instructed to inhale as deeply as possible and then exhale forcefully and completely until no further air could be expelled. During this procedure, the following parameters were measured: forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and peak expiratory flow (PEF). VO₂max was assessed using a gas analyzer (Quark CPET ® , Cosmed, Rome, Italy), electrocardiogram system (Heartwave II ® , Cambridge Heart Inc., Tewksbury, MA, USA), and a treadmill ergometer (T150, HP/Cosmos ® , Bavaria, Germany). Electrodes for electrocardiography were placed on the chest, and a blood pressure cuff was applied to the brachial artery of the right arm for continuous measurement of blood pressure and heart rate. A respiratory mask was fitted to each participant’s face to prevent air leakage while allowing for accurate breath-by-breath gas analysis through both the mouth and nose. The modified Bruce protocol was employed to evaluate the aerobic work capacity of older adults 29 . Participants were encouraged to walk or run on the treadmill until they reached their maximal perceived exertion. Throughout the test, participants were continuously monitored for signs of chest pain, dyspnea, dizziness, or leg discomfort. The test was terminated if any of the following criteria were met: (a) participant request to stop; (b) progressive neurological symptoms; (c) moderate to severe angina; (d) signs of cyanosis; (e) a drop in systolic blood pressure ≥ 10 mmHg from baseline despite increasing workload, accompanied by ischemic symptoms; (f) sustained ventricular tachycardia; or (g) ST-segment elevation >1 mm in leads without pathological Q waves 24 . Blood collection, myokines, and immunocytes Twenty mL of blood was drawn from the forearm vein using a disposable syringe while participants were seated. Samples were collected from the median cubital vein after a 10-h overnight fast using three types of BD Vacutainer ® tubes (BD Biosciences, Franklin Lakes, NJ, USA): a K₂-EDTA tube for differential blood cell counts, a heparin tube for flow cytometric analysis, and a serum separator tube (SST™) for myokine detection. Serum samples were centrifuged at 1,500 × g for 10 minutes at 4°C to separate plasma and peripheral blood mononuclear cells (PBMC). Plasma samples were aliquoted and stored at −80°C until cytokine analysis. Plasma levels of IL-6, IL-10, and IL-12 were quantified using commercially available enzyme-linked immunosorbent assay (ELISA) kits (IL-6, Cat.#D6050; IL-10, Cat.#217-ILB; IL-12 [p70] Cat.#554613) according to the manufacturer’s protocols (R&D Systems, Minneapolis, MN, USA). Standards and plasma samples were added to 96-well plates pre-coated with cytokine-specific capture antibodies. After incubation, biotin-conjugated detection antibodies were applied, followed by streptavidin-HRP. Color development was achieved using tetramethylbenzidine substrate, and absorbance was measured at 450 nm using a microplate reader. Myokine concentrations were calculated from standard curves, and all measurements were performed in duplicate. Each sample was analyzed in duplicate, and myokine concentrations were reported as the mean values in pg/mL 2 . PBMC were isolated by density gradient centrifugation using Ficoll-Paque and resuspended in staining buffer. For flow cytometric analysis, cells were incubated with fluorochrome-conjugated monoclonal antibodies against surface markers specific for macrophages (CD14⁺, CD16⁺), dendritic cells (CD11⁺), and T lymphocytes (CD3⁺, CD4⁺, CD8⁺), B lymphocytes (CD19⁺), and NK cells (CD56⁺) 30 . Samples were incubated in the dark at room temperature for 15 min, followed by erythrocytes lysis using fluorescence-activated cell sorting (FACS) lysing solution for an additional 15 min. Subsequent analysis was performed using a FACS Canto II flow cytometer (BD Biosciences, USA) and FlowJo software (Treestar, Ashland, OR, USA). The percentages and absolute counts of each immunocytes population were determined. Additionally, optical density was measured at 450 nm with wavelength correction at 540 nm using a Tecan Sunrise microplate reader (Tecan Group Ltd., Männedorf, Switzerland), following previous protocols 7 . Statistical analysis Data were expressed as mean ± standard deviation and analysed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA), while graphical representations were generated with GraphPad Prism 10.6.1 (La Jolla, CA, USA). The distribution of all data was evaluated for normality using the Kolmogorov–Smirnov test. Categorical variables are expressed as n (%) and were compared using either the χ² test or Fisher’s exact test, as appropriate. Prior to the main analyses, baseline differences between groups were examined by applying the Mann‒Whitney U to the pre-intervention values of the variables. For normally distributed data, repeated-measures ANOVA was applied for variable comparisons. For nonnormally distributed data, the Mann‒Whitney U test was used to analyse differences between groups. Intragroup changes were evaluated via the Wilcoxon signed-rank test. A detailed analysis involved calculating the Δ% for each period. Effect sizes (η²) were interpreted as small, moderate, or large based on thresholds of 0.2, 0.5, and 0.8 for parametric measures and 0.1, 0.3, and 0.5 for nonparametric measures, respectively 31 . Statistical significance was set at p ≤ 0.05. Results Demographic characteristics A total of 69 older adults were allocated to either the CON ( n = 35; 22 males and 13 females) or the FTH ( n = 34; 21 males and 13 females). Baseline demographic and clinical variables did not differ significantly between groups (Table 1). The chronic diseases (e.g., osteoporosis, obesity, hypertension, diabetes, and arthritis) were comparable between the two groups, with no statistically significant differences observed. Prior to the intervention, sleep duration was 6.1 ± 0.7 h in CON and 6.2 ± 0.7 h in FTH. Following the intervention, it decreased to 5.7 ± 0.7 h in CON but increased to 6.9 ± 0.7 h in FTH, yielding a significant interaction effect ( p = 0.001, η² = 0.265). The Δ% analysis revealed a decrease of −6.1 ± 13.1% in the CON, whereas the FTH exhibited an increase of 12.4 ± 18.5%, demonstrating a significant between-group difference ( p < 0.001). Caloric intake at baseline was 1768.1 ± 106.9 kcal in the CON and 1724.2 ± 153.7 kcal in the FTH. After 12 weeks, it decreased by −1.9 ± 15.5% in the CON and increased by 1.5 ± 12.8% in the FTH; however, no significant differences were observed between the groups. Baseline PA levels were comparable between groups (CON: 413.5 ± 51.6 MET∙min/week; FTH: 412.3 ± 47.0 MET∙min/week). Post-intervention, the Δ% analysis of PA showed a decrease of −5.1 ± 22.6% in the CON and an increase of 193.7 ± 45.8% in the FTH, indicating a significant between-group difference ( p < 0.001). Skeletal muscle oxygen saturation Fig. 3 presents the individual changes in SmO₂ for participants in the CON (C#1–#35) and FTH (#1–#34) groups, along with a comparative analysis of the mean SmO₂ across different intervals. The mean SmO₂ levels in the VL progressively declined at the 60- and 90-min marks, revealing significant differences between the two groups. Body composition and cardiopulmonary function Body mass index and fat mass increased in the CON but decreased in the FTH, whereas muscle mass declined in the CON but improved in the FTH. These opposing trends resulted in significant between-group differences across all body composition parameters (Table 2, Fig. 4a-d). At follow-up, VO₂max, FVC, FEV₁, and PEF declined in the CON but improved in the FTH, yielding significant between-group and interaction effects (Table 2). VO₂max decreased in the CON (−9.7 ± 12.4%) but increased in the FTH (11.2 ± 7.8%) (Fig. 4e). Similar patterns were observed for FVC (−12.5 ± 16.2% vs. +13.6 ± 24.7%) (Fig. 4f), FEV₁ (−19.5 ± 18.8% vs. +10.1 ± 21.3%) (Fig. 4g), and PEF (−5.6 ± 11.3% vs. +13.0 ± 15.4%) (Fig. 4h), with all outcomes demonstrating significant between-group differences. Myokines, immunocytes, and lymphocytes subtypes Circulating IL-6 increased in the CON but decreased in the FTH, while IL-10 and IL-12 declined in the CON but increased in the FTH. Except for eosinophils and basophils, the remaining immunocytes tended to decrease in the CON, whereas they showed an increasing trend in the FTH (Table 3). Fig. 5 depicts the Δ% changes in myokines and immunocytes between groups. IL-6 increased in the CON (8.2 ± 31.8%) but decreased in the FTH (−17.0 ± 26.7%) (Fig. 5a), while IL-10 (Fig. 5b) and IL-12 (Fig. 5c) decreased in the CON (−6.8 ± 25.8% and −17.8 ± 22.6%) but increased in the FTH (29.2 ± 28.5% and 12.4 ± 34.0%), all showing significant between-group differences. Similarly, leukocytes (−1.8 ± 19.0% vs. +16.9 ± 24.3%), lymphocytes (−7.2 ± 21.9% vs. +12.7 ± 23.7% as shown in Fig. 5d), neutrophils (−3.5 ± 24.5% vs. +12.2 ± 21.9% as shown in Fig. 5e), monocytes (−12.0 ± 32.6% vs. +10.0 ± 34.0% as shown in Fig. 5f), macrophages CD14 (−5.4 ± 32.4% vs. +17.0 ± 39.1% as shown in Fig. 5g), macrophages CD16 (−10.3 ± 26.3% vs. +9.2 ± 24.2%), and dendrocytes (−6.3 ± 23.9% vs. +26.6 ± 43.5% as shown in Fig. 5h), all decreased in the CON but increased in the FTH, with significant between-group differences observed across variables. Following the intervention, cell populations ranging from NK to CD19⁺ B cells tended to decrease in the CON, whereas they exhibited an increasing trend in the FTH, resulting in a significant interaction effect (Table 3). In the Fig. 5i, NK cells declined in the CON (−15.8 ± 41.8%) but increased in the FTH (+42.7 ± 42.5%). Similar patterns were observed for NKT (−11.9 ± 30.5% vs. +21.7 ± 35.5%) (Fig. 5j), CD3⁺ T (−10.6 ± 19.5% vs. +11.0 ± 18.5%) (Fig. 5k), CD4⁺ T (−11.4 ± 19.8% vs. +12.4 ± 23.0%) (Fig. 5l), CD8⁺ T (−12.4 ± 20.7% vs. +18.4 ± 43.8%) (Fig. 5m), and CD19⁺ B cells (−8.7 ± 26.1% vs. +15.4 ± 28.4%) (Fig. 5n), all demonstrating significant between-group differences. Discussion This study demonstrates that NIRS–based SmO₂ measurement enables continuous monitoring of muscle oxygen saturation during forest trail hiking across varying slopes, providing a sensitive indicator of muscle metabolism in older adults. SmO₂ reached its nadir between 60 and 90 min of hiking, followed by gradual recovery, confirming both the safety and adaptability of participants to the exercise regimen. The 12-week forest hiking induced significant improvements in body composition, cardiopulmonary function, and immunocytes parameters. Advancements in NIRS allow non-invasive assessment of skeletal muscle oxidative metabolism directly attached to the muscle 17,18 . Outdoor SmO₂ monitoring overcomes limitations of indoor studies and allows evaluation of exercise tolerance in older adults and clinical populations 27,32,33 . In this study, the Seoraksan National Park provided an ecologically relevant environment for examining physiological responses to forest-based exercise 34 . During the two-hour round-trip hike, cumulative elevation gain of 107 m, and walking speed of 3.1–3.8 km/h, SmO₂ decreased from 70–80% to below 10% at the near-peak phase, indicating substantial muscle metabolic demand. Importantly, the observed metabolic demands during forest hiking were associated with a marked improvement in VO₂max—a parameter closely linked to longevity in older adults 35 —which increased by 11.2 ± 7.8%. In addition, similar enhancements were observed in pulmonary function indices, including FVC, FEV₁, and PEF. Taken together, these findings suggest that forest hiking within ecological environments may serve as a highly suitable health-promotion model for older adults. Several studies suggest that the exposure to forest environments combined with walking has been reported to produce short-term improvements in certain respiratory function parameters, with detectable inhalation of some volatile compounds—possessing autonomic, anti-inflammatory, and antioxidant properties—appearing to directly contribute to these overall effects 36,37 . Recent research indicates that high-altitude exposure can reduce acute exacerbations of asthma 38 , and respiratory rehabilitation exercise conducted in mountainous environments may improve health-related quality of life and exercise capacity in patients with pulmonary disease 39,40 . The age-related decline in physical function is closely associated with immunosenescence. This process is characterized by reduced phagocytic capacity, decreased trafficking of dendritic cells, and increased secretion of pro-inflammatory cytokines, even in the absence of overt disease 41 . Importantly, diseases associated with chronic inflammation and elevated IL-6 levels are strongly linked to reductions in muscle mass and strength, both of which represent fundamental causes of physical disability in older adults. Conversely, IL-10 has been observed at higher levels in exceptionally healthy older adults 42 . In contrast, frail elderly exhibit lower IL-10 levels, accompanied by diminished antigen-presenting function of dendritic cells 43 . This evidence suggests that IL-10 plays a pivotal role in balancing inflammatory and anti-inflammatory pathways, thereby influencing resilience against age-related immune dysfunction, the preservation of muscle function, and the trajectory of healthy aging. Consistent with previous studies, the older adults in this study exhibited elevated levels of IL-6, whereas IL-10 showed an opposite pattern. However, the increase in the IL-10 and the decrease in the IL-6 observed in the FTH further support the hypothesis that forest-based exercise mediates systemic anti-inflammatory effects. In a similar study by Gerosa-Neto et al. 44 , the 16-week effects of three different exercise programs on inflammation profiles and insulin resistance were evaluated in overweight or obese participants. They reported that after 16 weeks, the high-intensity interval training group exhibited decreased IL-6 along with trends toward reductions in body weight. In the study by Jankord and Jemiolo 41 , the effects of regular PA and the presence of disease or disability on pro- and anti-inflammatory cytokine levels were examined in men aged 65–74 years. The highly active group showed significantly lower IL-6 levels and significantly higher IL-10 levels compared with the inactive group, indicating that exercise plays an important role in modulating inflammatory markers during aging. In addition to these changes, aging is accompanied by a decline in IL-12 production, an interleukin that plays a central role in bridging innate and adaptive immunity. IL-12 is critical for promoting CD4⁺ T cell differentiation and stimulating CD8⁺ T and NK cells activity. Reduced IL-12 secretion therefore undermines the antigen-presenting capacity of accessory cells such as dendritic cells, weakening the initiation of adaptive immune responses 45 . The results of this study demonstrated that forest walking led to an increase in IL-12 in the FTH, whereas it decreased in the CON, resulting in a 26.6 ± 43.5% elevation in dendritic cells, which in turn enhanced antigen-presenting capacity and the initiation of adaptive immune responses. Although macrophage levels in this study largely remained within the normal range, a decreasing trend was observed in the CON, whereas the FTH exhibited an increasing trend. This suggests that forest trail hiking may enhance the production of IL-12, a pivotal cytokine that bridges innate and adaptive immunity by promoting T-cells differentiation and stimulating NK cell activity. By supporting IL-12–mediated signalling, exercise in forested environments may improve antigen presentation and strengthen the coordination between macrophages, dendritic cells, and lymphocytes, thereby enhancing both innate and adaptive immune responses. These effects provide a mechanistic basis for the observed systemic anti-inflammatory benefits and suggest that forest-based PA can counteract aspects of immunosenescence in older adults 46 . In the context of these findings suggest that forest trail hiking induces anti-inflammatory effects in older adults, ultimately contributing to favourable improvements in immunocytes. Furthermore, while lymphocyte subpopulations decreased in the CON, the FTH demonstrated significant increases. The beneficial changes in immunocytes parameters, including increases in NK, NKT, T cells subpopulations and B cells, are particularly notable given that immunosenescence is a hallmark of aging and a major risk factor for infection, malignancy, and impaired vaccination response in older adults 47 . Previous studies have shown that regular moderate-intensity PA enhances immune surveillance and reduces chronic low-grade inflammation 48,49 . Our findings align with these observations and further suggest that exercise performed in forest environments may amplify these immunological benefits. According to a study on older men, participation in an aerobic exercise program conducted in both high- and low-phytoncide environments revealed that the combined effects of forest bathing and aerobic exercise enhanced immunocyte function by improving cardiorespiratory endurance and elevating epinephrine levels 34 . Furthermore, another study assigned 32 participants aged 61–79 years into four groups: a control group, an exercise-only group with minimal phytoncide exposure (EXE), a phytoncide-only group without exercise (PHYT), and a combined exercise plus phytoncide group (EXE+PHYT). The findings demonstrated that leukocyte and lymphocyte profiles improved in the EXE, PHYT, and EXE+PHYT, with total NK cells showing significant increases exclusively in the EXE+PHYT. Additionally, although cardiorespiratory endurance improved across all intervention groups, reductions in body weight and fat mass were observed only in the EXE+PHYT. Collectively, these age-related immune alterations impair immediate innate defenses and hinder the subsequent activation of adaptive immunity, thereby heightening susceptibility to infections, diminishing vaccine responsiveness, and accelerating immunosenescence 50 . These findings underscore the therapeutic potential of forest-based PA in counteracting age-associated declines in physiological and immunological function. However, the findings of this study have several limitations. Although muscle metabolism during forest walking was successfully assessed using NIRS, the sample size was relatively small. In addition, while the 12-week intervention period may be considered moderately long, it remains uncertain whether the observed effects would persist over a longer duration. Furthermore, despite the presence of numerous myokines and immune cell subtypes, not all could be examined in this study. Moreover, because the sample consisted of relatively healthy older adults, the generalizability of these findings may be limited. Future studies should address these limitations through larger, more diverse cohorts and extended follow-up assessments. Despite these limitations, this study suggests that a structured forest hiking program may serve as an effective and low-cost strategy to enhance muscle metabolism, promote favourable changes in body composition, and improve anti-inflammatory and immunological responses in older adults. Such interventions are particularly important in rapidly aging societies, where maintaining functional capacity and reducing healthcare burdens are critical public health priorities. Declarations Acknowledgements We sincerely thank all the patients who permitted us to use their data for this study. We also extend our gratitude to the researchers at the Seoul Songdo Hospital Immunocyte Laboratory. Authors’ contributions Y.-S.J. conceived the idea. S.-G.J. and Y.-S.J. developed the background and performed the calibrations of the different devices used in the tests. S.-G.J. and Y.-S.J. verified the methods section. All the authors discussed the results and contributed to the final manuscript. D.-H.Y. and S.-G.J. performed the tests. Y.-S.J. wrote the manuscript with support from both researchers. All the authors contributed to the final version of the manuscript. All the authors contributed to the interpretation of the results and data analysis, drafted the manuscript and designed the figures and tables. All the authors provided critical feedback and helped shape the research, analysis, and manuscript. All the authors have read and agreed to the published version of the manuscript. Funding The authors received no financial support from any funding agency for this study. Competing interests The authors declare no competing interests. Ethics Approved by the Hanseo University IRB (HS23-08-02) and registered in CRIS (KCT0008712). Consent to participate All participants provided written informed consent before participation, in accordance with institutional guidelines. Additional information Correspondence and reqeusts for materials should be addressed to Y.-S.J. Trial registration : This study was registered with the Clinical Research Information Service of the Korea Centers for Disease Control and Prevention under Clinical Trials KCT0008712 on 18/08/2023. References Statistics Korea. 2024 Statistics on the Aged . (Statistics Korea, Daejeon, 2024). Heo, S. J. & Jee, Y. S. Intensity-effects of strengthening exercise on thigh muscle volume, pro- or anti-inflammatory cytokines, and immunocytes in older adults: a randomized controlled trial. Arch. Gerontol. Geriatr. 116 , 105136 (2024). Nagano, A., Wakabayashi, H., Maeda, K., Kokura, Y., Miyazaki, S., Mori, T. & Fujiwara, D. Respiratory sarcopenia and sarcopenic respiratory disability: concepts, diagnosis, and treatment. J. Nutr. Health Aging 25 , 507–515 (2021). Trim, W., Turner, J. E. & Thompson, D. Parallels in immunometabolic adipose tissue dysfunction with ageing and obesity. Front. Immunol. 9 , 169 (2018). Vida, C., González, E. M. & De la Fuente, M. 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Behav. 284 , 114640 (2024). Tables Table 1. Demographic and anthropometric characteristics at baseline. Groups Mann-Whitney U Items CON ( n = 35) FTH ( n = 34) Z p η 2 General characteristics and health status Age 73.5 ± 3.2 72.7 ± 3.1 -0.921 0.357 0.014 Sex 1.4 ± 0.5 1.4 ± 0.5 -0.093 0.926 0.000 Family living 1.3 ± 0.5 1.4 ± 0.5 -0.831 0.406 0.010 Economic status 3.3 ± 0.4 3.1 ± 0.5 -1.071 0.284 0.020 Presence of chronic disease ‡ 2.6 ± 0.9 2.7 ± 1.0 -0.095 0.924 0.001 Level of social activity 2.8 ± 0.7 2.4 ± 0.9 -1.606 0.831 0.041 Family history of heart disease 0.3 ± 0.4 0.3 ± 0.5 -0.603 0.546 0.005 Smoking status 0.2 ± 0.4 0.3 ± 0.5 -0.900 0.368 0.012 Cardiovascular and respiratory symptoms Chest discomfort 0.1 ± 0.2 0.0 ± 0.2 -0.561 0.575 0.005 Dizziness 0.1 ± 0.4 0.1 ± 0.3 -0.309 0.758 0.001 Shortness of breath 0.1 ± 0.2 0.1 ± 0.3 -0.494 0.621 0.004 Ankle edema 0.1 ± 0.3 0.1 ± 0.3 -0.436 0.663 0.003 Palpitations 0.0 ± 0.2 0.1 ± 0.2 -0.612 0.541 0.006 Intermittent claudication 0.0 ± 0.2 0.0 ± 0.2 -0.021 0.984 0.000 Heart murmur 0.0 ± 0.1 0.0 ± 0.2 -1.350 0.177 0.027 Fatigue 0.0 ± 0.2 0.0 ± 0.2 -0.021 0.984 0.000 Body composition Height (cm) 162.2 ± 6.0 163.9 ± 6.6 -1.320 0.187 0.018 Body weight (kg) 66.8 ± 7.2 67.2 ± 11.0 -0.818 0.413 0.000 Body mass index (kg/m 2 ) 25.4 ± 2.3 24.9 ± 3.5 -0.289 0.773 0.006 Muscle mass (kg) 33.1 ± 6.0 32.4 ± 5.5 -1.246 0.213 0.004 Fat mass (kg) 19.2 ± 3.6 19.2 ± 4.8 -0.692 0.489 0.000 Sex and family living arrangement was coded as 1 for living alone and 2 for living with a spouse or family. Economic status was self-rated from 1 (very poor) to 4 (well-off). Chronic diseases were recorded as multiple responses, ranging from 0 to 14. Social activity was rated on a five-point scale, from 1 (very good) to 5 (very poor). Cardiovascular and respiratory risk factors and symptoms were coded as 1 (present) or 0 (absent). CON, control group; FTH, forest trail hiking group. Table 2. Comparative analysis of body composition and cardiopulmonary variables. Groups (G) p Time (T) CON ( n = 35) FTH ( n = 34) G T GT η 2 Body composition Body weight (kg) pre 66.8 ± 7.2 67.2 ± 11.0 0.292 0.558 <.001 0.257 post 69.2 ± 7.4 64.2 ± 11.2 BMI (kg/m 2 ) pre 25.4 ± 2.3 24.9 ± 3.5 0.034 0.580 <.001 0.255 post 26.3 ± 2.4 23.8 ± 3.3 Muscle mass (kg) pre 33.1 ± 6.0 32.4 ± 5.5 0.050 0.818 <.001 0.433 post 30.2 ± 4.2 35.6 ± 5.1 Fat mass (kg) pre 19.2 ± 3.6 19.2 ± 4.8 0.029 0.895 <.001 0.308 post 21.3 ± 4.3 17.1 ± 4.2 Cardiopulmonary factors VO₂max (mL/kg/min) pre 33.5 ± 5.3 35.8 ± 2.3 <.001 0.748 <.001 0.505 post 29.9 ± 4.5 39.7 ± 2.0 FVC (L) pre 2.8 ± 0.6 3.0 ± 0.9 0.003 0.483 <.001 0.278 post 2.4 ± 0.6 3.3 ± 0.9 FEV 1 (L) pre 2.2 ± 0.6 2.4 ± 0.6 <.001 0.010 <.001 0.314 post 1.8 ± 0.6 2.5 ± 0.5 PEF (L/s) pre 5.3 ± 2.0 5.9 ± 2.0 0.014 0.284 <.001 0.253 post 4.9 ± 1.4 6.6 ± 2.2 CON, control group; FTH, forest trail hiking group; BMI, body mass index; FVC, forced vital capacity; FEV 1 , forced expiratory volume in 1sec; PEF, peak expiratory flow. Table 3. Comparative analysis of myokines and immunocytes. Groups (G) p Time (T) CON ( n = 35) FTH ( n = 34) G T GT η 2 Myokines Interleukin 6 (pg/mL) pre 16.1 ± 3.3 16.1 ± 4.1 0.017 0.047 0.001 0.145 post 16.9 ± 4.2 13.0 ± 4.5 Interleukin 10 (pg/mL) pre 12.9 ± 2.2 13.0 ± 1.9 <.001 0.002 <.001 0.324 post 11.8 ± 3.5 16.8 ± 4.0 Interleukin 12 (pg/mL) pre 9.0 ± 3.2 8.6 ± 3.2 0.190 0.015 <.001 0.176 post 7.0 ± 2.4 9.1 ± 3.2 Immunocytes Leucocytes (×10³cells/uL) pre 4.7 ± 0.7 4.8 ± 0.6 <.001 0.045 0.001 0.145 post 4.5 ± 0.7 5.4 ± 0.8 Lymphocytes (%) pre 43.9 ± 10.1 43.5 ± 10.5 0.096 0.910 <.001 0.184 post 39.9 ± 10.4 47.8 ± 10.2 Neutrophils (%) pre 53.7 ± 10.9 52.3 ± 11.1 0.131 0.836 0.002 0.140 post 49.6 ± 7.4 56.9 ± 9.2 Monocytes (%) pre 4.9 ± 1.4 4.8 ± 1.2 0.052 0.122 0.007 0.104 post 4.0 ± 1.1 5.0 ± 1.4 Eosinophils (%) pre 3.9 ± 1.7 3.9 ± 1.1 0.590 0.443 0.392 0.011 post 3.6 ± 2.2 3.9 ± 1.2 Basophils (%) pre 0.6 ± 0.3 0.6 ± 0.3 0.222 0.353 0.123 0.035 post 0.5 ± 0.4 0.7 ± 0.4 Macrophages (%) pre 3.6 ± 1.2 3.5 ± 1.0 0.275 0.810 0.014 0.087 post 3.2 ± 0.9 3.8 ± 1.2 Macrophages (%) pre 0.6 ± 0.4 0.5 ± 0.3 0.672 0.057 <.001 0.245 post 0.5 ± 0.3 0.6 ± 0.3 Dendrocytes (%) pre 1.7 ± 0.5 1.6 ± 0.5 0.094 0.218 <.001 0.176 post 1.5 ± 0.5 1.9 ± 0.5 Lymphocytes subsets NK cells (%) pre 9.3 ± 3.1 9.2 ± 2.6 <.001 0.298 <.001 0.344 post 6.9 ± 2.6 12.6 ± 3.6 NK T cells (%) pre 2.9 ± 1.3 3.0 ± 1.3 0.073 0.740 <.001 0.180 post 2.4 ± 1.2 3.4 ± 1.4 CD3⁺ T cells (%) pre 65.2 ± 8.8 64.6 ± 7.4 0.004 0.812 <.001 0.228 post 58.2 ± 14.8 70.9 ± 9.2 CD4⁺ T cells (%) pre 41.4 ± 8.3 41.3 ± 8.8 0.015 0.562 <.001 0.224 post 36.0 ± 9.1 45.5 ± 9.8 CD8⁺ T cells (%) pre 24.5 ± 7.2 24.6 ± 6.8 0.016 0.610 0.002 0.141 post 20.7 ± 6.0 27.4 ± 7.9 CD19⁺ B cells (%) pre 22.1 ± 3.7 22.4 ± 4.7 0.002 0.893 <.001 0.178 post 19.7 ± 4.7 25.0 ± 5.0 CON, control group; FTH, forest trail hiking group; NK, natural killer. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Apr, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 07 Oct, 2025 Editor assigned by journal 06 Oct, 2025 Submission checks completed at journal 06 Oct, 2025 First submitted to journal 04 Oct, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7779628","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":525442444,"identity":"930315dc-39a3-48b3-8c11-2790c7088c1c","order_by":0,"name":"Sang-Geun Jo","email":"","orcid":"","institution":"Hanseo University","correspondingAuthor":false,"prefix":"","firstName":"Sang-Geun","middleName":"","lastName":"Jo","suffix":""},{"id":525442445,"identity":"0b178d5d-26c3-4adc-b57c-286a8aec45a1","order_by":1,"name":"Dong-Hyun Yoo","email":"","orcid":"","institution":"Hanseo University","correspondingAuthor":false,"prefix":"","firstName":"Dong-Hyun","middleName":"","lastName":"Yoo","suffix":""},{"id":525442446,"identity":"8160e768-db32-40be-8612-0ffa2f87f48b","order_by":2,"name":"Yong-Seok Jee","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYBACxgYQWXEAISJBnJYzpGiB6GsjRQtze/MxyZ/z7sib8x8++IChxo5BcvYB/FoYe46lSfNue2a4c0ZasgHDsWQGab4EAlpm5JhJM247zLjhBo+ZBAPbAQY5HgIOY5z//pvkzzmH7TecP/9NguEfMVpm8LBJ8DYcTtxwIIdNAhQO0gS19KQZW/McO5y84UaasUFiXzKPZA8BLYbthx/e/FFz2HbD+cMPH3z4ZicncYaQlgYGFkRMJDAwEHIWA4M8MGo+EFQ1CkbBKBgFIxsAAOWgQxivHjDkAAAAAElFTkSuQmCC","orcid":"","institution":"Hanseo University","correspondingAuthor":true,"prefix":"","firstName":"Yong-Seok","middleName":"","lastName":"Jee","suffix":""}],"badges":[],"createdAt":"2025-10-04 11:38:25","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7779628/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7779628/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-026-49821-4","type":"published","date":"2026-04-28T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":93024114,"identity":"6d76ff58-b545-4296-a465-823e48b4825b","added_by":"auto","created_at":"2025-10-08 09:13:49","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1309150,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscriptv1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/e26229dcd9324d2a43829a7f.docx"},{"id":93024118,"identity":"08df0c8d-cdd1-4320-af4f-75070e335745","added_by":"auto","created_at":"2025-10-08 09:13:49","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":5711,"visible":true,"origin":"","legend":"","description":"","filename":"6ee0d7b716cd4c938f0d4fde5b403034.json","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/ea8587a38bc91e9f2976d050.json"},{"id":93024112,"identity":"674f07f5-b139-4a7d-8c55-1f7a29132146","added_by":"auto","created_at":"2025-10-08 09:13:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":282659,"visible":true,"origin":"","legend":"\u003cp\u003eCONSORT diagram\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/e91d89e44ada3742862445f8.png"},{"id":93024113,"identity":"f0a8da08-afa8-485b-88fb-34cfe7603e6f","added_by":"auto","created_at":"2025-10-08 09:13:49","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1920570,"visible":true,"origin":"","legend":"\u003cp\u003eForest trail hiking course (ground elevation: 0.39 km)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/2d79480677be53439d08a04e.png"},{"id":93024117,"identity":"5025fc29-dfd0-4b3a-86b8-8cf5459a562a","added_by":"auto","created_at":"2025-10-08 09:13:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":457695,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of SmO₂ levels in individuals of the control group and forest trail hiking group. \u003csup\u003e****\u003c/sup\u003e indicates \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.0001.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/2b32985aa70071765a9c1e22.png"},{"id":93024119,"identity":"399fc8ff-41ea-4fa2-81c5-8bc1e5c4f797","added_by":"auto","created_at":"2025-10-08 09:13:50","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":559922,"visible":true,"origin":"","legend":"\u003cp\u003eDifferences in body composition and cardiopulmonary markers. CON, control group; FTH, forest trail hiking group. \u003csup\u003e****\u003c/sup\u003e indicates \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.0001 between groups.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/36dcbc8e2c7e1d87f358880a.png"},{"id":93024115,"identity":"40912430-f093-4b5a-84e8-27340b5c6a3e","added_by":"auto","created_at":"2025-10-08 09:13:49","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":717523,"visible":true,"origin":"","legend":"\u003cp\u003eDifferences and changes in myokines, immunocytes, and lymphocytes’ subtypes. CON, control group; FTH, forest trail hiking group. \u003csup\u003e*, **, ***, \u003c/sup\u003eand\u003csup\u003e **** \u003c/sup\u003eindicate \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, and \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.0001, respectively.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/3220072d9530b8238caf535f.png"},{"id":108437934,"identity":"3d655160-2e74-440c-822e-c8fee23a183a","added_by":"auto","created_at":"2026-05-04 16:04:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4726724,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7779628/v1/13eb45b3-0ee8-4680-a455-a88b6a7471ce.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Monitoring muscle oxygen saturation during forest trail hiking: A randomized controlled trial of physiological and immunological observations in older adults","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSouth Korea is experiencing one of the world\u0026rsquo;s most rapid demographic transitions, with adults aged \u0026ge; 65 years already comprising nearly one-fifth of the population and projected to exceed 40% by 2050. Although life expectancy continues to rise, ageing is accompanied by increased medical costs, reduced life satisfaction, and progressive functional decline\u003csup\u003e1\u003c/sup\u003e. Central to this decline is sarcopenia, the age-related loss of muscle mass and strength\u003csup\u003e2\u003c/sup\u003e, which not only impairs mobility but also compromises respiratory muscles essential for cardiopulmonary function\u003csup\u003e3\u003c/sup\u003e. Accumulation of adipose tissue has been shown to exacerbate systemic inflammation through increased release of pro-inflammatory cytokines, notably interleukin (IL)-6, while simultaneously impairing the cytotoxic activity of natural killer (NK) cells and the functional competence of T lymphocytes. These immuno-metabolic disturbances are considered key mechanisms that accelerate senescence, compromise physiological resilience, and ultimately worsen survival outcomes\u003csup\u003e4,5\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eRegular engagement in physical activity (PA) not only mitigates the onset of sarcopenia and preserves cardiopulmonary function but also exerts beneficial immunomodulatory effects by enhancing anti-inflammatory mediators, such as IL-10 or IL-12, and promoting the activity of critical innate and adaptive immune cell populations\u003csup\u003e6,7\u003c/sup\u003e. In the context of PA-induced muscle metabolism, myokines serve as pivotal mediators by promoting immunocyte functionality, attenuating adipose tissue accumulation, and mitigating oxidative stress\u0026ndash;related damage. Walking has been reported to enhance skeletal muscle metabolism, promote immune homeostasis, and upregulate anti-inflammatory mediators\u003csup\u003e2,8\u003c/sup\u003e.\u0026nbsp;Phytoncides released from forests are also known to reduce inflammation and enhance immunocytes activity, suggesting that performing the aforementioned walking in a forest environment may provide additional benefits for older adults\u003csup\u003e9\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eForest hiking refers to a form of PA performed along designated walking or trekking paths within forest environments, incorporating varying slopes and terrains\u003csup\u003e10\u003c/sup\u003e. Forest-based activities, often referred to as \u0026quot;forest healing\u0026quot;, have been shown to lower stress hormone, improve mood, and enhance immunocytes, through the inhalation of phytoncides released by trees\u003csup\u003e11,12\u003c/sup\u003e.\u0026nbsp;This concept encompasses restorative interventions carried out in forest mountain, utilizing the unique physical and environmental characteristics of forests to support health recovery and improvement\u003csup\u003e13,14\u003c/sup\u003e. While forest trail hiking may offer substantially greater benefits for older adults compared with walking in general environments\u003csup\u003e15\u003c/sup\u003e, it nevertheless presents certain drawbacks.\u0026nbsp;In other words, the physiological monitoring of older adults during forest-based activity remains challenging, particularly on ever-changing trails where oxygen delivery and utilization are difficult to assess\u003csup\u003e16,17\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eNear-infrared spectroscopy (NIRS) is a non-invasive technique capable of providing functional insights into skeletal muscle oxidative metabolism during PA in both healthy individuals and clinical populations. When applied to forest trail settings, NIRS may help minimize research limitations and enable the assessment of exercise performance and tolerance in older adults\u003csup\u003e17,18\u003c/sup\u003e, thereby offering valuable evidence for evaluating the feasibility of forest trail interventions in this population. In other words, the use of NIRS to measure skeletal muscle oxygen saturation (SmO₂) holds potential for assessing muscle oxygen utilization not only in outdoor environments but also during forest trail hiking across varying slopes and terrains; however, research on its application under such conditions remains absent. Here, we report a randomized controlled trial designed to (i) characterize SmO₂ dynamics during forest trail hiking in older adults and (ii) evaluate the long-term effects of a 12-week program on body composition, cardiopulmonary function, and immune regulation. This integrated approach may address a critical gap in understanding how sustained, ecologically valid PA influences physiological and immunological ageing.\u003c/p\u003e"},{"header":"Methodology","content":"\u003cp\u003e\u003cstrong\u003eStudy design and participants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe conducted a prospective, double-blind, randomized controlled trial in community-dwelling older adults residing in two senior living facilities in Seoul, Korea (May\u0026ndash;August 2025). All procedures were conducted in accordance with the Declaration of Helsinki. The study was approved by the Hanseo University Ethics Committee (HS23-08-02) and registered with the Clinical Research Information Service (KCT0008712). All participants provided written informed consent. Eligible participants were aged 66\u0026ndash;78 years, nonsmokers, free from major cardiopulmonary, metabolic, or psychiatric disorders, and had not engaged in regular PA within six months. Participants were excluded if they had previously undergone weight reduction therapies, were currently taking medications that could influence body composition, or had undergone surgery within the past year. Individuals with a documented history of cardiovascular or cerebrovascular disease, malignancy, or psychiatric disorders were also excluded.\u003c/p\u003e\n\u003cp\u003eSample size estimation was performed using G*Power software (version 3.1.9.7; Heinrich-Heine-Universit\u0026auml;t, D\u0026uuml;sseldorf, Germany) with the following parameters: effect size f(V) = 0.25, \u0026alpha; error probability = 0.05, power (1\u0026ndash;\u0026beta;) = 0.95, number of groups = 2 (experimental vs. control), and number of measurements = 2 (pre- and post-intervention). The calculation indicated that a minimum of 54 was required\u003csup\u003e19\u003c/sup\u003e. To account for an anticipated dropout rate of 20%\u003csup\u003e20\u003c/sup\u003e, additional participants were recruited. As shown in Fig. 1, a total of 87 individuals were initially recruited from two separate facilities to minimize the possibility of cross-group communication. Thirteen participants were excluded either due to failure to meet the inclusion criteria or for personal reasons, leaving 74 participants who completed surveys and baseline assessments. Random allocation was conducted using a tag selection performed by two independent representatives. One facility was assigned to the control group (CON) and the other to the forest trail hiking group (FTH), each consisting of 37 participants at baseline. During the 12-week intervention, two participants in the CON were excluded due to incomplete SmO₂ measurements or missing data, resulting in 35 participants for the final analysis. In the FTH, two participants withdrew, and one dataset was missing, leaving 34 participants for analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntervention\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eForest trail hiking was conducted in the Osaek area of Seoraksan National Park, South Korea. Based on previously published studies\u003csup\u003e21,22\u003c/sup\u003e, a hiking course was selected to ensure\u0026nbsp;a low-to-moderate-to-high intensity\u0026nbsp;level for older adults\u0026rsquo; physical capacities.\u0026nbsp;Before beginning the hike, participants in the FTH performed stretching exercises for 10\u0026ndash;15 min, progressing from a seated to a standing position. Upon completion of the hiking session, they returned indoors and conducted another 10\u0026ndash;15 min of stretching, transitioning from a seated to a supine position.\u0026nbsp;The intervention was carried out over 12 weeks, with two sessions per week (Tuesdays and Fridays). As shown in Fig. 2, participants were instructed to complete a round-trip hike from the starting point to the designated return point within a target duration of 120 min.\u0026nbsp;The hiking program was designed to achieve an exercise intensity corresponding to 40\u0026ndash;80% of each participant\u0026rsquo;s maximal oxygen uptake (VO₂max), as determined through a pre-intervention treadmill-based\u0026nbsp;cardiopulmonary exercise testing. To ensure that this target intensity was maintained, each participant\u0026rsquo;s individualized heart rate range was programmed into a smartwatch provided for use during the intervention. Additionally, the rating of perceived exertion 10-point scale was employed at 10- to 20-min intervals to monitor subjective effort levels\u003csup\u003e23\u003c/sup\u003e. If a participant\u0026apos;s exertion exceeded the equivalent of 81% VO₂max, a rest period of 3 min was implemented. These rest periods were not counted toward the total 120-min hiking duration goal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOutcome m\u003c/strong\u003e\u003cstrong\u003eeasures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eBaseline characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDemographic variables included living arrangement (1 = living alone; 2 = living with spouse or family) and self-reported economic status (1 = very poor; 2 = poor; 3 = average; 4 = well-off). Physician-diagnosed chronic conditions were recorded as multiple responses and included: none, osteoporosis, overweight, obesity, otorhinolaryngologic disease, endocrine disease, urological disease, dyslipidaemia, liver disease, spinal deformity, hypertension, diabetes, gastrointestinal disease, and arthritis. Social activity level was rated on a five-point scale (1 = very good; 5 = very poor). Cardiovascular and respiratory symptoms were coded as present (1) or absent (0) for the following: family history of premature heart surgery or sudden cardiac death, smoking within the past 6 months, chest pain or discomfort, dizziness or syncope, dyspnoea while sitting or lying down, ankle edema unrelated to prolonged standing, palpitations, intermittent claudication, history of heart murmur, and shortness of breath or unusual fatigue during normal activity\u003csup\u003e24\u003c/sup\u003e. Daily sleep duration was recorded by noting the time of falling asleep and calculating the interval until waking the following morning and commencing routine daily activities, which was then defined as the \u0026quot;sleep duration.\u0026quot; Daily caloric intake was assessed using meal plans designed by a registered dietitian. A single researcher entered the dietary data into the CAN-Pro 5.0 program (http://canpro5.kns.or.kr; Korean Nutrition Society) to record and analyze the daily intake of all participants. Daily PA levels were estimated using the International PA Questionnaire\u0026ndash;Short Form\u003csup\u003e25,26\u003c/sup\u003e. Sleep duration, daily caloric intake, and PA levels were recorded daily from the beginning to the end of the intervention. These data were aggregated on a monthly basis and averaged for comparative analysis between the pre- and post-intervention periods.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMuscle oxygen saturation measure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study measured SmO₂ using a near-infrared spectroscopy device, the Moxy Monitor (Muscle Oxygen Monitor, Fortiori Design LLC, Hutchinson, MN, USA). Measurements are taken at four distinct wavelengths, resulting in eight individual readings per cycle. The default sampling rate cycles through these wavelengths 80 times every 2 sec, producing an output frequency of 0.5 Hz\u0026nbsp;\u003csup\u003e27\u003c/sup\u003e. During the forest trail hiking sessions, the sensor was attached to the vastus lateralis (VL) using hypoallergenic, low-adhesive patches designed to be gentle on sensitive skin. To ensure stability at the attachment site without applying excessive pressure to the muscle, the sensor was further secured using a fixation strap.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrimary outcomes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll primary outcomes were assessed at 7:00 a.m., the scheduled wake-up time, with participants reporting to the designated testing area in a predetermined sequence.\u003c/p\u003e\n\u003cp\u003eBody composition\u003c/p\u003e\n\u003cp\u003eAll participants had their height and body composition measured using an InBody 720 (Biospace Co., Ltd., Seoul, Korea) while wearing light clothing and no metallic accessories, after voiding 30 min prior. Standing on the device\u0026rsquo;s platform and holding the handles for 3 min, measurements of height, body weight, muscle mass, fat mass, and body mass index were obtained. This bioelectrical impedance analysis method has been reported to show a high correlation with dual-energy X-ray absorptiometry\u003csup\u003e28\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eCardiopulmonary function\u003c/p\u003e\n\u003cp\u003ePulmonary function was assessed using a metabolic analyzer (Quark CPET\u003csup\u003e\u0026reg;\u003c/sup\u003e, Omnia software, version 1.6.7, Cosmed, Rome, Italy). All participants were instructed to inhale as deeply as possible and then exhale forcefully and completely until no further air could be expelled. During this procedure, the following parameters were measured: forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and peak expiratory flow (PEF). VO₂max was assessed using a gas analyzer (Quark CPET\u003csup\u003e\u0026reg;\u003c/sup\u003e, Cosmed, Rome, Italy), electrocardiogram system (Heartwave II\u003csup\u003e\u0026reg;\u003c/sup\u003e, Cambridge Heart Inc., Tewksbury, MA, USA), and a treadmill ergometer (T150, HP/Cosmos\u003csup\u003e\u0026reg;\u003c/sup\u003e, Bavaria, Germany). Electrodes for electrocardiography were placed on the chest, and a blood pressure cuff was applied to the brachial artery of the right arm for continuous measurement of blood pressure and heart rate. A respiratory mask was fitted to each participant\u0026rsquo;s face to prevent air leakage while allowing for accurate breath-by-breath gas analysis through both the mouth and nose. The modified Bruce protocol was employed to evaluate the aerobic work capacity of older adults\u003csup\u003e29\u003c/sup\u003e. Participants were encouraged to walk or run on the treadmill until they reached their maximal perceived exertion. Throughout the test, participants were continuously monitored for signs of chest pain, dyspnea, dizziness, or leg discomfort. The test was terminated if any of the following criteria were met: (a) participant request to stop; (b) progressive neurological symptoms; (c) moderate to severe angina; (d) signs of cyanosis; (e) a drop in systolic blood pressure \u0026ge; 10 mmHg from baseline despite increasing workload, accompanied by ischemic symptoms; (f) sustained ventricular tachycardia; or (g) ST-segment elevation \u0026gt;1 mm in leads without pathological Q waves\u003csup\u003e24\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eBlood collection, myokines, and immunocytes\u003c/p\u003e\n\u003cp\u003eTwenty mL of blood was drawn from the forearm vein using a disposable syringe while participants were seated. Samples were collected from the median cubital vein after a 10-h overnight fast using three types of BD Vacutainer\u003csup\u003e\u0026reg;\u003c/sup\u003e tubes (BD Biosciences, Franklin Lakes, NJ, USA): a K₂-EDTA tube for differential blood cell\u0026nbsp;counts, a heparin tube for flow cytometric analysis, and a serum separator tube (SST\u0026trade;) for myokine detection. Serum samples were centrifuged at 1,500 \u0026times; g for 10 minutes at 4\u0026deg;C to separate plasma and peripheral blood mononuclear cells (PBMC). Plasma samples were aliquoted and stored at \u0026minus;80\u0026deg;C until cytokine analysis.\u003c/p\u003e\n\u003cp\u003ePlasma levels of IL-6, IL-10, and IL-12 were quantified using commercially available enzyme-linked immunosorbent assay (ELISA) kits (IL-6, Cat.#D6050; IL-10, Cat.#217-ILB; IL-12 [p70] Cat.#554613) according to the manufacturer\u0026rsquo;s protocols (R\u0026amp;D Systems, Minneapolis, MN, USA). Standards and plasma samples were added to 96-well plates pre-coated with cytokine-specific capture antibodies. After incubation, biotin-conjugated detection antibodies were applied, followed by streptavidin-HRP. Color development was achieved using tetramethylbenzidine substrate, and absorbance was measured at 450 nm using a microplate reader. Myokine concentrations were calculated from standard curves, and all measurements were performed in duplicate. Each sample was analyzed in duplicate, and myokine concentrations were reported as the mean values in pg/mL\u003csup\u003e2\u003c/sup\u003e. PBMC were isolated by density gradient centrifugation using Ficoll-Paque and resuspended in staining buffer. For flow cytometric analysis, cells were incubated with fluorochrome-conjugated monoclonal antibodies against surface markers specific for macrophages (CD14⁺, CD16⁺), dendritic cells (CD11⁺), and T lymphocytes (CD3⁺, CD4⁺, CD8⁺), B lymphocytes (CD19⁺), and NK cells (CD56⁺)\u003csup\u003e30\u003c/sup\u003e. Samples were incubated in the dark at room temperature for 15 min, followed by erythrocytes lysis using fluorescence-activated cell sorting (FACS) lysing solution for an additional 15 min. Subsequent analysis was performed using a FACS Canto II flow cytometer (BD Biosciences, USA) and FlowJo software (Treestar, Ashland, OR, USA). The percentages and absolute counts of each immunocytes population were determined. Additionally, optical density was measured at 450 nm with wavelength correction at 540 nm using a Tecan Sunrise microplate reader (Tecan Group Ltd., M\u0026auml;nnedorf, Switzerland), following previous protocols\u003csup\u003e7\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Data were expressed as mean \u0026plusmn; standard deviation and analysed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA), while graphical representations were generated with GraphPad Prism 10.6.1 (La Jolla, CA, USA). The distribution of all data was evaluated for normality using the Kolmogorov\u0026ndash;Smirnov test. Categorical variables are expressed as \u003cem\u003en\u003c/em\u003e (%) and were compared using either the \u0026chi;\u0026sup2; test or Fisher\u0026rsquo;s exact test, as appropriate. Prior to the main analyses, baseline differences between groups were examined by applying the\u0026nbsp;Mann‒Whitney\u0026nbsp;U to the pre-intervention values of the variables. For\u0026nbsp;normally distributed data, repeated-measures ANOVA\u0026nbsp;was\u0026nbsp;applied for variable comparisons. For\u0026nbsp;nonnormally\u0026nbsp;distributed data, the\u0026nbsp;Mann‒Whitney\u0026nbsp;U test was\u0026nbsp;used\u0026nbsp;to analyse differences between groups.\u0026nbsp;Intragroup\u0026nbsp;changes were evaluated\u0026nbsp;via\u0026nbsp;the Wilcoxon signed-rank test. A detailed analysis involved calculating the \u0026Delta;% for each period. Effect sizes (\u0026eta;\u0026sup2;) were interpreted as small, moderate, or large based on\u0026nbsp;thresholds of 0.2, 0.5, and 0.8 for parametric measures and 0.1, 0.3, and 0.5 for\u0026nbsp;nonparametric\u0026nbsp;measures, respectively\u003csup\u003e31\u003c/sup\u003e.\u0026nbsp;Statistical significance was set at\u0026nbsp;\u003cem\u003ep\u003c/em\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026le; 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eDemographic characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 69 older adults were allocated to either the CON (\u003cem\u003en\u0026nbsp;\u003c/em\u003e= 35; 22 males and 13 females) or the FTH (\u003cem\u003en\u003c/em\u003e = 34; 21 males and 13 females). Baseline demographic and clinical variables did not differ significantly between groups (Table 1). The chronic diseases (e.g., osteoporosis, obesity, hypertension, diabetes, and arthritis) were comparable between the two groups, with no statistically significant differences observed.\u003c/p\u003e\n\u003cp\u003ePrior to the intervention, sleep duration\u0026nbsp;was 6.1 \u0026plusmn; 0.7 h in CON and 6.2 \u0026plusmn; 0.7 h in FTH. Following the intervention, it decreased to 5.7 \u0026plusmn; 0.7 h in CON but increased to 6.9 \u0026plusmn; 0.7 h in FTH, yielding a significant interaction effect (\u003cem\u003ep\u003c/em\u003e = 0.001, \u0026eta;\u0026sup2; = 0.265). The \u0026Delta;% analysis revealed a decrease of \u0026minus;6.1 \u0026plusmn; 13.1% in the CON, whereas the FTH exhibited an increase of 12.4 \u0026plusmn; 18.5%, demonstrating a significant between-group difference (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Caloric intake at baseline was 1768.1 \u0026plusmn; 106.9 kcal in the CON and 1724.2 \u0026plusmn; 153.7 kcal in the FTH. After 12 weeks, it decreased by \u0026minus;1.9 \u0026plusmn; 15.5% in the CON and increased by 1.5 \u0026plusmn; 12.8% in the FTH; however, no significant differences were observed between the groups. Baseline PA levels were comparable between groups (CON: 413.5 \u0026plusmn; 51.6 MET∙min/week; FTH: 412.3 \u0026plusmn; 47.0 MET∙min/week). Post-intervention, the \u0026Delta;% analysis of PA showed a decrease of \u0026minus;5.1 \u0026plusmn; 22.6% in the CON and an increase of 193.7 \u0026plusmn; 45.8% in the FTH, indicating a significant between-group difference (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSkeletal muscle oxygen saturation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFig. 3 presents the individual changes in SmO₂ for participants in the CON (C#1\u0026ndash;#35) and FTH (#1\u0026ndash;#34) groups, along with a comparative analysis of the mean SmO₂ across different intervals. The mean SmO₂ levels in the VL progressively declined at the 60- and 90-min marks, revealing significant differences between the two groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eBody composition and cardiopulmonary function\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBody mass index and fat mass increased in the CON but decreased in the FTH, whereas muscle mass declined in the CON but improved in the FTH. These opposing trends resulted in significant between-group differences across all body composition parameters (Table 2, Fig. 4a-d).\u003c/p\u003e\n\u003cp\u003eAt follow-up, VO₂max, FVC, FEV₁, and PEF declined in the CON but improved in the FTH, yielding significant between-group and interaction effects (Table 2).\u0026nbsp;VO₂max decreased in the CON (\u0026minus;9.7 \u0026plusmn; 12.4%) but increased in the FTH (11.2 \u0026plusmn; 7.8%) (Fig. 4e). Similar patterns were observed for FVC (\u0026minus;12.5 \u0026plusmn; 16.2% vs. +13.6 \u0026plusmn; 24.7%) (Fig. 4f), FEV₁ (\u0026minus;19.5 \u0026plusmn; 18.8% vs. +10.1 \u0026plusmn; 21.3%) (Fig. 4g), and PEF (\u0026minus;5.6 \u0026plusmn; 11.3% vs. +13.0 \u0026plusmn; 15.4%) (Fig. 4h), with all outcomes demonstrating significant between-group differences.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMyokines, immunocytes, and lymphocytes subtypes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCirculating IL-6 increased in the CON but decreased in the FTH, while IL-10 and IL-12 declined in the CON but increased in the FTH. Except for eosinophils and basophils, the remaining immunocytes tended to decrease in the CON, whereas they showed an increasing trend in the FTH (Table 3).\u0026nbsp;Fig. 5 depicts the \u0026Delta;% changes in myokines and immunocytes between groups. IL-6 increased in the CON (8.2 \u0026plusmn; 31.8%) but decreased in the FTH (\u0026minus;17.0 \u0026plusmn; 26.7%) (Fig. 5a), while IL-10 (Fig. 5b) and IL-12 (Fig. 5c) decreased in the CON (\u0026minus;6.8 \u0026plusmn; 25.8% and \u0026minus;17.8 \u0026plusmn; 22.6%) but increased in the FTH (29.2 \u0026plusmn; 28.5% and 12.4 \u0026plusmn; 34.0%), all showing significant between-group differences. Similarly, leukocytes (\u0026minus;1.8 \u0026plusmn; 19.0% vs. +16.9 \u0026plusmn; 24.3%), lymphocytes (\u0026minus;7.2 \u0026plusmn; 21.9% vs. +12.7 \u0026plusmn; 23.7% as shown in Fig. 5d), neutrophils (\u0026minus;3.5 \u0026plusmn; 24.5% vs. +12.2 \u0026plusmn; 21.9% as shown in Fig. 5e), monocytes (\u0026minus;12.0 \u0026plusmn; 32.6% vs. +10.0 \u0026plusmn; 34.0% as shown in Fig. 5f), macrophages CD14 (\u0026minus;5.4 \u0026plusmn; 32.4% vs. +17.0 \u0026plusmn; 39.1% as shown in Fig. 5g), macrophages CD16 (\u0026minus;10.3 \u0026plusmn; 26.3% vs. +9.2 \u0026plusmn; 24.2%), and dendrocytes (\u0026minus;6.3 \u0026plusmn; 23.9% vs. +26.6 \u0026plusmn; 43.5% as shown in Fig. 5h), all decreased in the CON but increased in the FTH, with significant between-group differences observed across variables.\u003c/p\u003e\n\u003cp\u003eFollowing the intervention, cell populations ranging from NK to CD19⁺ B cells tended to decrease in the CON, whereas they exhibited an increasing trend in the FTH, resulting in a significant interaction effect (Table 3). In the Fig. 5i, NK cells declined in the CON (\u0026minus;15.8 \u0026plusmn; 41.8%) but increased in the FTH (+42.7 \u0026plusmn; 42.5%). Similar patterns were observed for NKT (\u0026minus;11.9 \u0026plusmn; 30.5% vs. +21.7 \u0026plusmn; 35.5%) (Fig. 5j), CD3⁺ T (\u0026minus;10.6 \u0026plusmn; 19.5% vs. +11.0 \u0026plusmn; 18.5%) (Fig. 5k), CD4⁺ T (\u0026minus;11.4 \u0026plusmn; 19.8% vs. +12.4 \u0026plusmn; 23.0%) (Fig. 5l), CD8⁺ T (\u0026minus;12.4 \u0026plusmn; 20.7% vs. +18.4 \u0026plusmn; 43.8%) (Fig. 5m), and CD19⁺ B cells (\u0026minus;8.7 \u0026plusmn; 26.1% vs. +15.4 \u0026plusmn; 28.4%) (Fig. 5n), all demonstrating significant between-group differences.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study demonstrates that NIRS\u0026ndash;based SmO₂ measurement enables continuous monitoring of muscle oxygen saturation during forest trail hiking across varying slopes, providing a sensitive indicator of muscle metabolism in older adults. SmO₂ reached its nadir between 60 and 90 min of hiking, followed by gradual recovery, confirming both the safety and adaptability of participants to the exercise regimen. The 12-week forest hiking induced significant improvements in body composition, cardiopulmonary function, and immunocytes parameters.\u003c/p\u003e\n\u003cp\u003eAdvancements in NIRS allow non-invasive assessment of skeletal muscle oxidative metabolism directly attached to the muscle\u003csup\u003e17,18\u003c/sup\u003e. Outdoor SmO₂ monitoring overcomes limitations of indoor studies and allows evaluation of exercise tolerance in older adults and clinical populations\u003csup\u003e27,32,33\u003c/sup\u003e. In this study, the Seoraksan National Park provided an ecologically relevant environment for examining physiological responses to forest-based exercise\u003csup\u003e34\u003c/sup\u003e. During the two-hour round-trip hike, cumulative elevation gain of 107 m, and walking speed of 3.1\u0026ndash;3.8 km/h, SmO₂ decreased from 70\u0026ndash;80% to below 10% at the near-peak phase, indicating substantial muscle metabolic demand. Importantly, the observed metabolic demands during forest hiking were associated with a marked improvement in VO₂max\u0026mdash;a parameter closely linked to longevity in older adults\u003csup\u003e35\u003c/sup\u003e\u0026mdash;which increased by 11.2 \u0026plusmn; 7.8%. In addition, similar enhancements were observed in pulmonary function indices, including FVC, FEV₁, and PEF. Taken together, these findings suggest that forest hiking within ecological environments may serve as a highly suitable health-promotion model for older adults. Several studies suggest that the exposure to forest environments combined with walking has been reported to produce short-term improvements in certain respiratory function parameters, with detectable inhalation of some volatile compounds\u0026mdash;possessing autonomic, anti-inflammatory, and antioxidant properties\u0026mdash;appearing to directly contribute to these overall effects\u003csup\u003e36,37\u003c/sup\u003e. Recent research indicates that high-altitude exposure can reduce acute exacerbations of asthma\u003csup\u003e38\u003c/sup\u003e, and respiratory rehabilitation exercise conducted in mountainous environments may improve health-related quality of life and exercise capacity in patients with pulmonary disease\u003csup\u003e39,40\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe age-related decline in physical function is closely associated with immunosenescence. This process is characterized by reduced phagocytic capacity, decreased trafficking of dendritic cells, and increased secretion of pro-inflammatory cytokines, even in the absence of overt disease\u003csup\u003e41\u003c/sup\u003e. Importantly, diseases associated with chronic inflammation and elevated IL-6 levels are strongly linked to reductions in muscle mass and strength, both of which represent fundamental causes of physical disability in older adults. Conversely, IL-10 has been observed at higher levels in exceptionally healthy older adults\u003csup\u003e42\u003c/sup\u003e. In contrast, frail elderly exhibit lower IL-10 levels, accompanied by diminished antigen-presenting function of dendritic cells\u003csup\u003e43\u003c/sup\u003e. This evidence suggests that IL-10 plays a pivotal role in balancing inflammatory and anti-inflammatory pathways, thereby influencing resilience against age-related immune dysfunction, the preservation of muscle function, and the trajectory of healthy aging. Consistent with previous studies, the older adults in this study exhibited elevated levels of IL-6, whereas IL-10 showed an opposite pattern. However, the increase in the IL-10 and the decrease in the IL-6 observed in the FTH further support the hypothesis that forest-based exercise mediates systemic anti-inflammatory effects. In a similar study by Gerosa-Neto et al.\u003csup\u003e44\u003c/sup\u003e, the 16-week effects of three different exercise programs on inflammation profiles and insulin resistance were evaluated in overweight or obese participants. They reported that after 16 weeks, the high-intensity interval training group exhibited decreased IL-6 along with trends toward reductions in body weight.\u0026nbsp;In the study by Jankord and Jemiolo\u003csup\u003e41\u003c/sup\u003e, the effects of regular PA and the presence of disease or disability on pro- and anti-inflammatory cytokine levels were examined in men aged 65\u0026ndash;74 years. The highly active group showed significantly lower IL-6 levels and significantly higher IL-10 levels compared with the inactive group, indicating that exercise plays an important role in modulating inflammatory markers during aging.\u003c/p\u003e\n\u003cp\u003eIn addition to these changes, aging is accompanied by a decline in IL-12 production, an interleukin that plays a central role in bridging innate and adaptive immunity. IL-12 is critical for promoting CD4⁺ T cell differentiation and stimulating CD8⁺ T and NK cells activity. Reduced IL-12 secretion therefore undermines the antigen-presenting capacity of accessory cells such as dendritic cells, weakening the initiation of adaptive immune responses\u003csup\u003e45\u003c/sup\u003e. The results of this study demonstrated that forest walking led to an increase in IL-12 in the FTH, whereas it decreased in the CON, resulting in a 26.6 \u0026plusmn; 43.5% elevation in dendritic cells, which in turn enhanced antigen-presenting capacity and the initiation of adaptive immune responses. Although macrophage levels in this study largely remained within the normal range, a decreasing trend was observed in the CON, whereas the FTH exhibited an increasing trend. This suggests that forest trail hiking may enhance the production of IL-12, a pivotal cytokine that bridges innate and adaptive immunity by promoting T-cells differentiation and stimulating NK cell activity. By supporting IL-12\u0026ndash;mediated signalling, exercise in forested environments may improve antigen presentation and strengthen the coordination between macrophages, dendritic cells, and lymphocytes, thereby enhancing both innate and adaptive immune responses. These effects provide a mechanistic basis for the observed systemic anti-inflammatory benefits and suggest that forest-based PA can counteract aspects of immunosenescence in older adults\u003csup\u003e46\u003c/sup\u003e. In the context of these findings suggest that forest trail hiking induces anti-inflammatory effects in older adults, ultimately contributing to favourable improvements in immunocytes. Furthermore, while lymphocyte subpopulations decreased in the CON, the FTH demonstrated significant increases. The beneficial changes in immunocytes parameters, including increases in NK, NKT, T cells subpopulations and B cells, are particularly notable given that immunosenescence is a hallmark of aging and a major risk factor for infection, malignancy, and impaired vaccination response in older adults\u003csup\u003e47\u003c/sup\u003e. Previous studies have shown that regular moderate-intensity PA enhances immune surveillance and reduces chronic low-grade inflammation\u003csup\u003e48,49\u003c/sup\u003e. Our findings align with these observations and further suggest that exercise performed in forest environments may amplify these immunological benefits.\u0026nbsp;According to a study on older men, participation in an aerobic exercise program conducted in both high- and low-phytoncide environments revealed that the combined effects of forest bathing and aerobic exercise enhanced immunocyte function by improving cardiorespiratory endurance and elevating epinephrine levels\u003csup\u003e34\u003c/sup\u003e. Furthermore, another study assigned 32 participants aged 61\u0026ndash;79 years into four groups: a control group, an exercise-only group with minimal phytoncide exposure (EXE), a phytoncide-only group without exercise (PHYT), and a combined exercise plus phytoncide group (EXE+PHYT). The findings demonstrated that leukocyte and lymphocyte profiles improved in the EXE, PHYT, and EXE+PHYT, with total NK cells showing significant increases exclusively in the EXE+PHYT. Additionally, although cardiorespiratory endurance improved across all intervention groups, reductions in body weight and fat mass were observed only in the EXE+PHYT. Collectively, these age-related immune alterations impair immediate innate defenses and hinder the subsequent activation of adaptive immunity, thereby heightening susceptibility to infections, diminishing vaccine responsiveness, and accelerating immunosenescence\u003csup\u003e50\u003c/sup\u003e.\u0026nbsp;These findings underscore the therapeutic potential of forest-based PA in counteracting age-associated declines in physiological and immunological function.\u003c/p\u003e\n\u003cp\u003eHowever, the findings of this study have several limitations. Although muscle metabolism during forest walking was successfully assessed using NIRS, the sample size was relatively small. In addition, while the 12-week intervention period may be considered moderately long, it remains uncertain whether the observed effects would persist over a longer duration. Furthermore, despite the presence of numerous myokines and immune cell subtypes, not all could be examined in this study. Moreover, because the sample consisted of relatively healthy older adults, the generalizability of these findings may be limited. Future studies should address these limitations through larger, more diverse cohorts and extended follow-up assessments. Despite these limitations, this study suggests that a structured forest hiking program may serve as an effective and low-cost strategy to enhance muscle metabolism, promote favourable changes in body composition, and improve anti-inflammatory and immunological responses in older adults. Such interventions are particularly important in rapidly aging societies, where maintaining functional capacity and reducing healthcare burdens are critical public health priorities.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe sincerely thank all the patients who permitted us to use their data for this study. We also extend our gratitude to the researchers at the Seoul Songdo Hospital Immunocyte Laboratory.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eY.-S.J. conceived the idea. S.-G.J. and Y.-S.J. developed the background and performed the calibrations of the different devices used in the tests. S.-G.J. and Y.-S.J. verified the methods section. All the authors discussed the results and contributed to the final manuscript. D.-H.Y. and S.-G.J. performed the tests. Y.-S.J. wrote the manuscript with support from both researchers. All the authors contributed to the final version of the manuscript. All the authors contributed to the interpretation of the results and data analysis, drafted the manuscript and designed the figures and tables. All the authors provided critical feedback and helped shape the research, analysis, and manuscript. All the authors have read and agreed to the published version of the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors received no financial support from any funding agency for this study.\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\u003eEthics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eApproved by the Hanseo University IRB (HS23-08-02) and registered in CRIS (KCT0008712).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll participants provided written informed consent before participation, in accordance with institutional guidelines.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCorrespondence and reqeusts for materials should be addressed to Y.-S.J.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e: This study was registered with the Clinical Research Information Service of the Korea Centers for Disease Control and Prevention under Clinical Trials KCT0008712 on 18/08/2023.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eStatistics Korea. \u003cem\u003e2024 Statistics on the Aged\u003c/em\u003e. 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Monit.\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 6375\u0026ndash;6386 (2018).\u003c/li\u003e\n \u003cli\u003eJankord, R. \u0026amp; Jemiolo, B. Influence of physical activity on serum IL-6 and IL-10 levels in healthy older men. \u003cem\u003eMed. Sci. Sports Exerc.\u003c/em\u003e \u003cstrong\u003e36\u003c/strong\u003e, 960\u0026ndash;964 (2004).\u003c/li\u003e\n \u003cli\u003eMoore, K. W., de Waal Malefyt, R., Coffman, R. L. \u0026amp; O\u0026rsquo;Garra, A. Interleukin-10 and the interleukin-10 receptor. \u003cem\u003eAnnu. Rev. Immunol.\u003c/em\u003e \u003cstrong\u003e19\u003c/strong\u003e, 683\u0026ndash;765 (2001).\u003c/li\u003e\n \u003cli\u003eUyemura, K., Castle, S. C. \u0026amp; Makinodan, T. The frail elderly: role of dendritic cells in the susceptibility of infection. \u003cem\u003eMech. Ageing Dev.\u003c/em\u003e \u003cstrong\u003e123\u003c/strong\u003e, 955\u0026ndash;962 (2002).\u003c/li\u003e\n \u003cli\u003eGerosa-Neto, J. \u003cem\u003eet al.\u003c/em\u003e Impact of long-term high-intensity interval and moderate-intensity continuous training on subclinical inflammation in overweight/obese adults. \u003cem\u003eJ. Exerc. Rehabil.\u003c/em\u003e \u003cstrong\u003e12\u003c/strong\u003e, 575\u0026ndash;580 (2016).\u003c/li\u003e\n \u003cli\u003eMbongue, J., Nicholas, D., Firek, A. \u0026amp; Langridge, W. The role of dendritic cells in tissue-specific autoimmunity. \u003cem\u003eJ. Immunol. Res.\u003c/em\u003e \u003cstrong\u003e2014\u003c/strong\u003e, 857143 (2014).\u003c/li\u003e\n \u003cli\u003eTimmerman, K. L. \u003cem\u003eet al.\u003c/em\u003e Exercise training-induced lowering of inflammatory (CD14+CD16+) monocytes: a role in the anti-inflammatory influence of exercise? \u003cem\u003eJ. Leukoc. Biol.\u003c/em\u003e \u003cstrong\u003e84\u003c/strong\u003e, 1271\u0026ndash;1278 (2008).\u003c/li\u003e\n \u003cli\u003eMazur, M. \u003cem\u003eet al.\u003c/em\u003e Effects of controlled physical activity on immune cell phenotype in peripheral blood in prehypertension\u0026mdash;studies in preclinical model and randomised crossover study. \u003cem\u003eJ. Physiol. Pharmacol.\u003c/em\u003e \u003cstrong\u003e69\u003c/strong\u003e, (2018).\u003c/li\u003e\n \u003cli\u003eCampbell, J. P. \u0026amp; Turner, J. E. Debunking the myth of exercise-induced immune suppression: redefining the impact of exercise on immunological health across the lifespan. \u003cem\u003eFront. Immunol.\u003c/em\u003e \u003cstrong\u003e9\u003c/strong\u003e, 648 (2018).\u003c/li\u003e\n \u003cli\u003eNieman, D. C. \u0026amp; Wentz, L. M. The compelling link between physical activity and the body\u0026rsquo;s defense system. \u003cem\u003eJ. Sport Health Sci.\u003c/em\u003e \u003cstrong\u003e8\u003c/strong\u003e, 201\u0026ndash;217 (2019).\u003c/li\u003e\n \u003cli\u003ePark, S. K., Park, S. \u0026amp; Jee, Y. S. Effects of physical inactivity behavior during COVID-19 pandemic on physical fitness, body composition, inflammatory cytokine, and immunocytes in older adults: a retrospective and prospective study. \u003cem\u003ePhysiol. Behav.\u003c/em\u003e \u003cstrong\u003e284\u003c/strong\u003e, 114640 (2024).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" align=\"\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" style=\"width: 602px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1.\u003c/strong\u003e Demographic and anthropometric characteristics at baseline.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 195px;\"\u003e\n \u003cp\u003eGroups\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u003cu\u003eMann-Whitney U\u003c/u\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eItems\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eCON (\u003cem\u003en\u003c/em\u003e = 35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003eFTH (\u003cem\u003en\u0026nbsp;\u003c/em\u003e= 34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003eZ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u0026eta;\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" style=\"width: 602px;\"\u003e\n \u003cp\u003e\u003cu\u003eGeneral characteristics and health status\u003c/u\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eAge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e73.5 \u0026plusmn; 3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e72.7 \u0026plusmn; 3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.921\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.357\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.014\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e1.4 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e1.4 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.093\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.926\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eFamily living\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e1.3 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e1.4 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.831\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.406\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.010\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eEconomic status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e3.1 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-1.071\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.284\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.020\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003ePresence of chronic disease\u003csup\u003e\u0026Dagger;\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e2.6 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e2.7 \u0026plusmn; 1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.095\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.924\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eLevel of social activity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e2.8 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e2.4 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-1.606\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.831\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.041\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eFamily history of heart disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.3 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.3 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.603\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.546\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eSmoking status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.2 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.3 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.900\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.368\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" style=\"width: 602px;\"\u003e\n \u003cp\u003e\u003cu\u003eCardiovascular and respiratory symptoms\u003c/u\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eChest discomfort\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.561\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.575\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eDizziness\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.309\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.758\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eShortness of breath\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.494\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.621\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eAnkle edema\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.436\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.663\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003ePalpitations\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.1 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.541\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eIntermittent claudication\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.984\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eHeart murmur\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-1.350\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.177\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.027\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eFatigue\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 98px;\"\u003e\n \u003cp\u003e0.0 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.984\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" style=\"width: 602px;\"\u003e\n \u003cp\u003e\u003cu\u003eBody composition\u003c/u\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eHeight (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e162.2 \u0026plusmn; 6.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e163.9 \u0026plusmn; 6.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-1.320\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.187\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 61px;\"\u003e\n \u003cp\u003e0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eBody weight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e66.8 \u0026plusmn; 7.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e67.2 \u0026plusmn; 11.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.818\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.413\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 61px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eBody mass index (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e25.4 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e24.9 \u0026plusmn; 3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.289\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.773\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 61px;\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eMuscle mass (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e33.1 \u0026plusmn; 6.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e32.4 \u0026plusmn; 5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-1.246\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.213\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 61px;\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eFat mass (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e19.2 \u0026plusmn; 3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e19.2 \u0026plusmn; 4.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 66px;\"\u003e\n \u003cp\u003e-0.692\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 60px;\"\u003e\n \u003cp\u003e0.489\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 61px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 1px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 1px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 1px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSex and family living arrangement was coded as 1 for living alone and 2 for living with a spouse or family. Economic status was self-rated from 1 (very poor) to 4 (well-off). Chronic diseases were recorded as multiple responses, ranging from 0 to 14. Social activity was rated on a five-point scale, from 1 (very good) to 5 (very poor). Cardiovascular and respiratory risk factors and symptoms were coded as 1 (present) or 0 (absent).\u003c/p\u003e\n\u003cp\u003eCON, control group; FTH, forest trail hiking group.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" align=\"\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"8\" style=\"width: 594px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Comparative analysis of body composition and cardiopulmonary variables.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 177px;\"\u003e\n \u003cp\u003eGroups (G)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u003cu\u003ep\u003c/u\u003e\u003c/em\u003e\u003cem\u003e\u003cu\u003e \u003c/u\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(T)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003eCON\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(\u003cem\u003en\u0026nbsp;\u003c/em\u003e= 35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003eFTH\u003c/p\u003e\n \u003cp\u003e(\u003cem\u003en\u003c/em\u003e = 34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003eG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003eT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003eGT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026eta;\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eBody composition\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eBody weight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e66.8 \u0026plusmn; 7.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e67.2 \u0026plusmn; 11.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.292\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.558\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.257\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e69.2 \u0026plusmn; 7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e64.2 \u0026plusmn; 11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e25.4 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e24.9 \u0026plusmn; 3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.034\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.580\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.255\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e26.3 \u0026plusmn; 2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e23.8 \u0026plusmn; 3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eMuscle mass (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e33.1 \u0026plusmn; 6.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e32.4 \u0026plusmn; 5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.050\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.818\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.433\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e30.2 \u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e35.6 \u0026plusmn; 5.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eFat mass (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e19.2 \u0026plusmn; 3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e19.2 \u0026plusmn; 4.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.029\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.895\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.308\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e21.3 \u0026plusmn; 4.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e17.1 \u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eCardiopulmonary factors\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eVO₂max (mL/kg/min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e33.5 \u0026plusmn; 5.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e35.8 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.748\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.505\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e29.9 \u0026plusmn; 4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e39.7 \u0026plusmn; 2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eFVC (L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e2.8 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e3.0 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.483\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.278\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e2.4 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003eFEV\u003csub\u003e1\u003c/sub\u003e(L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e2.2 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e2.4 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.010\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.314\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e1.8 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e2.5 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\n \u003cp\u003ePEF (L/s)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e5.3 \u0026plusmn; 2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e5.9 \u0026plusmn; 2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.014\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.284\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\n \u003cp\u003e0.253\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 163px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 45px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 88px;\"\u003e\n \u003cp\u003e4.9 \u0026plusmn; 1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e6.6 \u0026plusmn; 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 53px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"8\" style=\"width: 594px;\"\u003e\n \u003cp\u003eCON, control group; FTH, forest trail hiking group; BMI, body mass index; FVC, forced vital capacity; FEV\u003csub\u003e1\u003c/sub\u003e, forced expiratory volume in 1sec; PEF, peak expiratory flow.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" align=\"\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"8\" style=\"width: 602px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e Comparative analysis of myokines and immunocytes.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 185px;\"\u003e\n \u003cp\u003eGroups (G)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u003cu\u003ep\u0026nbsp;\u003c/u\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003eTime (T)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003eCON\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(\u003cem\u003en\u0026nbsp;\u003c/em\u003e= 35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eFTH\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(\u003cem\u003en\u003c/em\u003e = 34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003eG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003eT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003eGT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026eta;\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMyokines\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eInterleukin 6 (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e16.1 \u0026plusmn; 3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e16.1 \u0026plusmn; 4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.047\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.145\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e16.9 \u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e13.0 \u0026plusmn; 4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eInterleukin 10 (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e12.9 \u0026plusmn; 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e13.0 \u0026plusmn; 1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.324\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e11.8 \u0026plusmn; 3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e16.8 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eInterleukin 12 (pg/mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e9.0 \u0026plusmn; 3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e8.6 \u0026plusmn; 3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.190\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.176\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e7.0 \u0026plusmn; 2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e9.1 \u0026plusmn; 3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eImmunocytes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eLeucocytes (\u0026times;10\u0026sup3;cells/uL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e4.7 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e4.8 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.045\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.145\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e4.5 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e5.4 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eLymphocytes (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e43.9 \u0026plusmn; 10.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e43.5 \u0026plusmn; 10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.096\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.910\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.184\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e39.9 \u0026plusmn; 10.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e47.8 \u0026plusmn; 10.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eNeutrophils (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e53.7 \u0026plusmn; 10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e52.3 \u0026plusmn; 11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.131\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.836\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.140\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e49.6 \u0026plusmn; 7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e56.9 \u0026plusmn; 9.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMonocytes (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e4.9 \u0026plusmn; 1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e4.8 \u0026plusmn; 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.052\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.122\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.104\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e4.0 \u0026plusmn; 1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e5.0 \u0026plusmn; 1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eEosinophils (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.590\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.443\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.392\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.011\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e3.6 \u0026plusmn; 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eBasophils (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e0.6 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.6 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.222\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.353\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.035\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e0.5 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.7 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMacrophages (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e3.6 \u0026plusmn; 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.5 \u0026plusmn; 1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.275\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.810\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.014\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.087\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e3.2 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.8 \u0026plusmn; 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMacrophages (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e0.6 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.5 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.672\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.057\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.245\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e0.5 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e0.6 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eDendrocytes (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e1.7 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e1.6 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.094\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.218\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.176\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e1.5 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e1.9 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eLymphocytes subsets\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eNK cells (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e9.3 \u0026plusmn; 3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e9.2 \u0026plusmn; 2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.298\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.344\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e6.9 \u0026plusmn; 2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e12.6 \u0026plusmn; 3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eNK T cells (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e2.9 \u0026plusmn; 1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.0 \u0026plusmn; 1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.073\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.740\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.180\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e2.4 \u0026plusmn; 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e3.4 \u0026plusmn; 1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eCD3⁺\u0026nbsp;T cells (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e65.2 \u0026plusmn; 8.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e64.6 \u0026plusmn; 7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.812\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.228\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e58.2 \u0026plusmn; 14.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e70.9 \u0026plusmn; 9.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eCD4⁺\u0026nbsp;T cells (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e41.4 \u0026plusmn; 8.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e41.3 \u0026plusmn; 8.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.562\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.224\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e36.0 \u0026plusmn; 9.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e45.5 \u0026plusmn; 9.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eCD8⁺\u0026nbsp;T cells (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e24.5 \u0026plusmn; 7.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e24.6 \u0026plusmn; 6.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.610\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.141\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e20.7 \u0026plusmn; 6.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e27.4 \u0026plusmn; 7.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eCD19⁺\u0026nbsp;B cells (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e22.1 \u0026plusmn; 3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e22.4 \u0026plusmn; 4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.893\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e\u0026lt;.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\n \u003cp\u003e0.178\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 168px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003epost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp\u003e19.7 \u0026plusmn; 4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e25.0 \u0026plusmn; 5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 52px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"8\" style=\"width: 602px;\"\u003e\n \u003cp\u003eCON, control group; FTH, forest trail hiking group; NK, natural killer.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Forest trail hiking, Older adults, Skeletal muscle oxygen saturation, Immunity","lastPublishedDoi":"10.21203/rs.3.rs-7779628/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7779628/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eForest-based physical activity (PA) has been proposed as a strategy to counteract age-associated declines in health, yet its mechanistic underpinnings remain unclear. Muscle oxygen saturation (SmO₂) may serve as a real-time marker of physiological adaptation during PA. We conducted a 12-week randomized controlled trial in 69 older adults (aged 66–78 years), comparing forest trail hiking (FTH, \u003cem\u003en\u003c/em\u003e = 34) with a control group (CON, \u003cem\u003en \u003c/em\u003e= 35). Participants in the FTH engaged in progressive low- to high-intensity hiking (120 min, twice weekly). SmO₂ of the vastus lateralis was continuously monitored, and pre- and post-intervention assessments included body composition, cardiopulmonary performance, and immunological markers.\u003c/p\u003e\n\u003cp\u003eDuring hiking, SmO₂ declined progressively, reaching a nadir at 60–90 min before partial recovery. After 12 weeks, the FTH group showed reduced body fat, increased muscle mass, and improved VO₂max, FVC, FEV₁, and PEF, whereas the CON group exhibited adverse trends. Immunological changes included decreased IL-6 and increased IL-10 and IL-12 in the FTH, alongside enhanced lymphocyte subsets. Ultimately, continuous SmO₂ monitoring provides an informative marker of muscle oxygen dynamics during prolonged outdoor activity. Forest trail hiking elicited broad physiological and immunological benefits in older adults, underscoring its therapeutic potential for healthy ageing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e This study was retrospectively registered with the Clinical Research Information Service of the Korea Centers for Disease Control and Prevention under Clinical Trials KCT0008712 on 18/08/2023.\u003c/p\u003e","manuscriptTitle":"Monitoring muscle oxygen saturation during forest trail hiking: A randomized controlled trial of physiological and immunological observations in older adults","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-08 09:13:44","doi":"10.21203/rs.3.rs-7779628/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-07T10:50:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-06T14:05:58+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-06T14:05:03+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-10-04T11:33:05+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e7fd55b9-b943-4eab-b9c3-e9bcf770428b","owner":[],"postedDate":"October 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":55841775,"name":"Health sciences/Diseases"},{"id":55841776,"name":"Health sciences/Health care"},{"id":55841777,"name":"Health sciences/Medical research"},{"id":55841778,"name":"Biological sciences/Physiology"}],"tags":[],"updatedAt":"2026-05-04T16:03:52+00:00","versionOfRecord":{"articleIdentity":"rs-7779628","link":"https://doi.org/10.1038/s41598-026-49821-4","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-04-28 15:57:43","publishedOnDateReadable":"April 28th, 2026"},"versionCreatedAt":"2025-10-08 09:13:44","video":"","vorDoi":"10.1038/s41598-026-49821-4","vorDoiUrl":"https://doi.org/10.1038/s41598-026-49821-4","workflowStages":[]},"version":"v1","identity":"rs-7779628","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7779628","identity":"rs-7779628","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}