Investigating and Comparing the Diagnostic Value of Exercise Test Protocols in Pediatrics: A Shorter Alternative to the Bruce Method

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The standard Bruce protocol, though effective, is lengthy and can challenge compliance, especially in children. Objective This study evaluates the diagnostic value of the modified 4-minute and 8-minute exercise test protocols compared to the standard 21-minute Bruce protocol in terms of sensitivity, specificity, accuracy, and tolerance among children. Materials & Methods In this epidemiological analytical study 76 children under the age of 18 who had an indication for exercise testing were recruited. The study included three exercise protocols: standard Bruce protocol, modified 4-minute Bruce protocol, and modified 8-minute Bruce protocol. Tests were randomly assigned using a simple randomization software into two groups. After an 8–12-minute recovery period, participants switched protocols, ensuring each group completed all three tests. Data were analyzed using SPSS version 24. Descriptive statistics included measures of central tendency, dispersion, and frequency percentages. Sensitivity, specificity, and diagnostic accuracy were calculated for each protocol. Paired t-tests were used for within-group comparisons, while unpaired t-tests assessed differences between groups. Results In this study, 76 patients, 44 boys and 32 girls, were examined. The age of the children varied from 5 to 17 years; we compared the qualitative variables with the standard B method; In most cases, the variables had similar results in the three methods, and we checked the agreement between the two methods with Kappa statistics, which were significant (SIG < 0.05) and its VALUE was closer to 1, which means they were in 100% agreement. Conclusion This study found no significant differences in clinical outcomes among the Bruce, 4-minute, and 8-minute protocols in children. Therefore, the shorter 4-minute and 8-minute protocols can be effectively used as alternatives to the standard Bruce method. Exercise test treadmill ECG heart rate arrhythmia Figures Figure 1 Introduction Exercise testing (ET) is a non-invasive method used to access cardiovascular performance under stress and detect potential abnormalities for both adults and children( 1 ). It effectively evaluates the adequacy of blood supply to the heart muscles through the coronary arteries and assesses overall heart function. The test is conducted in a controlled environment under the supervision of experienced medical personnel. During the test, technicians closely monitor the patient's heart rate, respiratory rate, blood pressure, heart rhythm, and fatigue level. The most common form of stress testing involves walking on a treadmill. If the initial test reveals abnormal heart function during exercise, additional diagnostic tools such as echocardiography or nuclear imaging may be utilized to refine the diagnosis( 2 ). Although treadmill ET has some limitations, it remains a practical and user-friendly method, especially in pediatric populations, making it a preferred option for many physicians. One significant advantage of this method its versatility, as it can be used for patients of all ages, including children as young as three years old( 3 ). However, greater attention must be given to safety considerations when testing young children( 1 ). There is ongoing debate about the optimal methodology for exercise testing in children. Several protocols involving cycle ergometer or treadmill have been developed in this age group( 4 ). The Bruce treadmill protocol, one of the most widely used standards, was initially introduced by Bruce et al.( 5 ) for adults. Subsequently, Cumming et al. provided normative data on exercise responses and endurance times for 327 children aged 4 to 14 years( 6 ). This protocol is now widely accepted for use in the pediatric population as well( 1 ). In the Bruce protocol, patients progress through stages that require walking at increasingly faster speeds and steeper inclines. The standard protocol consists of seven stages, each lasting three minutes, but it can be extended to ten stages, although most patients do not complete all stages. The test begins at speed of 1.7 mph (2.7 km/h) and a 10% incline. At the end of each three-minute stage, both speed and incline are increased by approximately 1 mph and 2°, respectively( 7 ). The Bruce protocol is applicable to all age groups, allowing for comparative data as a child grows( 3 ). Moreover, reference values for children are available( 6 ). Despite its utility, the Bruce protocol has some drawbacks. Its monotonous and physically demanding nature, combined with substantial workload increments, can make it tiresome and challenging for children, especially those with cardiac conditions or limited physical fitness. These factors necessitate frequent encouragement to ensure children complete the test( 3 , 8 ). The modified Bruce protocol offers an alternative with adding two lower workload warmup stages to the start of the standard Bruce protocol. These stages, each lasting three minutes, require less exertion than stage 1 of the standard protocol. The first stage involves walking at 1.7 mph with no incline (0%), and the second at 1.7 mph with a 5% incline. This modified protocol is particularly beneficial for individuals who are unable to perform vigorous exercise, including older adults and those with reduced exercise capacity due to cardiac conditions( 9 , 10 ). Because the many medical diagnostic tools, firstly designed for adult group, some of these methods are not suitable for children. Although modified Bruce protocol seems suitable, practical method for children but exam of better protocols with shorter duration ET can lead to better corporation of little child with same ET diagnostic goals( 11 ). Given the absence of a universally accepted protocol for pediatric exercise testing, we proposed shorter versions of the Bruce protocol lasting four and eight minutes. This study aimed to compare the sensitivity, characteristics, and accuracy of these shorter protocols with the standard 21-minute Bruce protocol, which is widely used in clinical practice. Additionally, the study evaluated and compared the hemodynamic responses, incidence of arrhythmias, and functional capacity across all three protocols. Methods Study Design This epidemiological analytical study aimed to evaluate and compare exercise stress testing protocols in pediatric patients. The design was inspired by the methodology outlined in a previous study by Thiago Teixeira da Silveira Fagundes( 12 ) This research project Accepted by MUMS research council, No: 4010918. Informed written consent to participate in the study was provided by all participants (or their parent or legal guardian in the case of children under 16). Participant Preparation Participants were instructed to fast for several hours before the test to avoid discomfort or nausea, although small amounts of fluids were allowed. Caffeinated beverages, including coffee, tea, soda, and chocolate, were strictly prohibited. Before the test, a medical technician prepared the participants by applying electrodes to the skin for electrocardiogram (ECG) monitoring and fitting a blood pressure cuff on the arm. Exercise Test Protocol The exercise test began with a resting ECG, followed by a slow warm-up phase of two to three minutes on the treadmill. Participants gradually increased their speed and incline every two to three minutes until reaching their maximum capacity. Throughout the test, the supervising physician encouraged participants to continue until symptoms such as fatigue, dizziness, pain, or shortness of breath prompted termination. Post-exercise, participants rested in a sitting or lying position for approximately 10 minutes, during which heart rate and blood pressure were closely monitored. Participants were also queried about their fatigue levels or any faintness. If the ECG indicated potential abnormalities, the test was terminated, and further examinations were conducted. Protocol Comparison The study included three exercise protocols: Standard Bruce Protocol Modified 4-Minute Bruce Protocol Modified 8-Minute Bruce Protocol Tests were randomly assigned using a simple randomization software into two groups. After an 8–12-minute recovery period, participants switched protocols, ensuring each group completed all three tests. Outcomes and Measurements The primary measurable outcomes included: Exercise duration (seconds) Resting and maximum heart rate (HR, bpm) HR at the first minute of recovery Resting and maximum systolic arterial pressure (SAP, mmHg) Maximum double product (DP = HR × SAP × 10³) Workload in metabolic equivalents (METs) ST-T changes, corrected QT interval (QTc), and arrhythmias Blood pressure and clinical symptoms Inclusion and Exclusion Criteria Inclusion Criteria: The inclusion criteria for this study consisted of patients aged 5–18 years who required further cardiac evaluation for one or more of the following conditions: chest pain accompanied by a positive family history, chest pain with active T wave changes during physical activity, suspected coronary abnormalities, or the need for an assessment of exercise capacity. Exclusion Criteria: The exclusion criteria included patients with atypical chest pain, unstable angina not controlled by medication, acute aortic dissection, acute myocarditis or pericarditis, significant and uncontrolled cardiac arrhythmias, severe symptomatic aortic stenosis, symptomatic and uncontrolled heart failure, respiratory conditions such as upper or lower respiratory diseases, or any blood, metabolic, or neurological disorders. Sample size and statistical analysis: Based on prior studies and the sensitivity of ECG in exercise testing, the sample size calculation was conducted using the formula for comparing two proportions. With an alpha level of 0.05, a beta level of 0.2, and proportion values of P1 = 0.55 and P2 = 0.78, the required sample size was determined to be 70 participants per group. Data were analyzed using SPSS version 24. Descriptive statistics included measures of central tendency, dispersion, and frequency percentages. Sensitivity, specificity, and diagnostic accuracy were calculated for each protocol. Paired t-tests were used for within-group comparisons, while unpaired t-tests assessed differences between groups. Receiver Operating Characteristic (ROC) curves were generated to compare the diagnostic performance of the protocols. A p-value of < 0.05 was considered statistically significant. Results The study included 76 pediatric patients aged 5–17 years. Of these, 44 (57.9%) were male, and 32 (42.1%) were female. Table 1 shows other demographic characteristics of the participants. Table 1 Demographic characteristics of the participants Parameter Age Weight BMI Mean 10.00 32.82 19.47 Std. Deviation 2.96 13.37 5.32 Minimum 5.00 14.00 11.83 Maximum 17.00 74.00 32.65 Percentiles 25 8.00 22.25 16.00 50 10.00 30.00 18.36 75 12.00 39.00 22.40 The participants then performed the exercise test based on the standard Bruce protocol, as well as the 4-minute and 8-minute protocols. Table 2 presents the details of each of these protocols. Table 2 Protocols characteristics Protocol Parameter Mean (± Std) Min Max 4-min EXCERCISE TIME (min) 7.82 (± 0.40) 5.35 8.04 Max Speed 6.78 (± 0.15) 5.50 6.80 Max Incline (%) 15.97 (± 0.23) 14.00 16.00 8-minute EXCERCISE TIME 11.35 (±0.89) 8.00 12.00 Max Speed 6.72 (± 0.29) 5.50 6.80 Max Incline 15.89 (± 0.45) 14.00 16.00 Bruce EXCERCISE TIME 15.81 (± 2.46) 3.55 21.80 Max Speed 6.88 (± 0.73) 5.50 8.00 Max Incline 14.97 (± 0.85) 13.00 16.00 Across all protocols, heart rate (HR) and blood pressure (BP) values followed expected physiological patterns, with no statistically significant differences among the 4-minute, 8-minute, and standard Bruce protocols as shown in Table 3 and Table 4 , respectively. Table 3 Changes in HR Protocol Measurement Mean (± Std) Min Max 4-minute Rest HR 116.81 (± 18.82) 72 187 Stage 1 HR 125.34 (±18.21) 71 199 Stage 2 HR 136.2 (±16.82) 95 188 Stage 3 HR 155.28 (±25.89) 104 311 Stage 4 HR 170.92 (±13.86) 141 201 Recovery 1 HR 151.65 (±20.70) 88 188 Recovery 2 HR 125.49 (±29.45) 70 225 Recovery 3 HR 117.11 (± 21.19) 68 207 Target HR 178.90 (±2.56) 173 187 Target HR Percent 100.68 (±12.48) 84.40 171.80 METs 13.55 (± 0.40) 10.20 13.60 8-minute Rest HR 120.2 (±18.54) 71 212 Stage 1 HR 128.21 (±20.66) 76 238 Stage 2 HR 155.68 (±117.44) 94 1137 Stage 3 HR 161.09 (± 23.84) 117 292 Stage 4 HR 176.35 (± 15.39) 143 214 Recovery 1 HR 156.83 (± 24.78) 45 206 Recovery 2 HR 133.12 (± 28.33) 71 245 Recovery 3 HR 124.91 (± 22.69) 83 198 Target HR 178.52 (±2.56) 173 183 Target HR Percent 103.97 (±14.66) 80.20 170.20 METs 13.41 (± 0.77) 10.20 13.60 Bruce Rest HR 110.4 (± 15.23) 76 137 Stage 1 HR 123.33 (± 15.16) 83 154 Stage 2 HR 136.72 (± 17.06) 99 179 Stage 3 HR 158.17 (± 19.61) 116 200 Stage 4 HR 174.69 (± 15.59) 135 204 Recovery 1 HR 153.43 (± 21.61) 91 188 Recovery 2 HR 123.09 (± 18.84) 69 155 Recovery 3 HR 119.57 (± 18.51) 74 176 Target HR 177.97 (± 5.41) 138 187 Target HR Percent 102.39 (±9.49) 78.00 137.40 METs 13.17 (± 1.77) 9.70 15.80 Table 4 Changes in BP Protocol Measurement Mean (± Std) Min (mmHg) Max (mmHg) 4-minute SYS 102.61 (± 11.72) 90 150 DIA 64.42 (±7.81) 50 95 HR BP 10668.57 (±2261.88) 6400.00 17272.50 8-minute SYS 103.72 (±14.35) 90 155 DIA 65.85 (± 9.29) 50 95 HR BP 11187.83(±3162.96) 5550.00 23120.00 Bruce SYS 105.75 (±?) 90 160 DIA 66.64 (±?) 55 110 HR BP 11820.50 (±?) 7120.00 22360.00 Additionally, changes in ST-T, clinical symptoms including weakness and chest pain, as well as the occurrence of arrhythmia in participants were examined, with the results presented in Table 5 . Table 5 Clinical Symptoms and Arrhythmias Across Protocols protocol Bruce 8 min 4min ST-T changes 0% 0% 0% weakness 2.6% 3.9% 2.6% Chest pain 35.5% 36.6% 31.4% Arrythmia 0% 0% 0% We compared the qualitative variables with standard method B; In most cases, the variables had similar results in the three methods, and we checked the agreement between the two methods with Kappa statistics, which were significant (SIG < 0.05) and its VALUE was closer to 1, which means they were in 100% agreement. Discussion Exercise testing is a practical and user-friendly tool for evaluating children suspected of having cardiac conditions. When appropriate case selection is conducted, it provides valuable insights into cardiac hemodynamics and electrophysiological status. The purposes of exercise testing vary and may include assessing physical capacity, identifying structural heart disease, or diagnosing conduction abnormalities. Under normal conditions, an increasing heart rate is the primary indicator of rising cardiac output, with the maximum heart rate serving as a key measure of VO2 peak. in this study, there were no significant differences in results across three ET protocols, indicating that they yield comparable outcomes in terms of cardiac performance. Similarly, Braden et al found no significant differences between treadmill and cycle testing( 13 ). BP is another critical variable in exercise testing, as both systolic and diastolic BP typically increase with advancing exercise stages. In our study, BP changes did not differ significantly among the Bruce protocol, 4-minute protocol, and 8-minute protocol. While some studies compare BP changes between treadmill and cycle ergometer tests, limited data exist regarding BP changes with varying treadmill test durations. Our findings suggest that peak BP can be achieved using shorter-duration protocols in children( 14 ). Metabolic equivalents (METs) are also important in pediatric exercise testing, offering a practical means of quantifying the energy cost of activity. METs serve as indicators of functional capacity and aerobic power, though scores may vary based on fitness levels, the presence of cardiac disease, submaximal effort, and other factors. In this study, no significant differences were observed in METs scores across the three protocols, further supporting the validity of shorter-duration tests. Additionally, there were no significant differences in arrhythmia occurrence among the three protocols, demonstrating their equivalent sensitivity for detecting exercise-induced arrhythmias. Clinical symptoms and tolerance levels also showed no significant variation, confirming that all three protocols are similarly effective for evaluating physical activity tolerance and cardiac health. Conclusion This study found no significant differences in clinical outcomes among the Bruce, 4-minute, and 8-minute protocols in children. Therefore, the shorter 4-minute and 8-minute protocols can be effectively used as alternatives to the standard Bruce method, with the added advantage of better cooperation from pediatric participants. Shorter-duration exercise test protocols are both feasible and accurate for achieving the goals of exercise testing. They are particularly beneficial for children with structural heart disease, systemic illnesses, or limited physical fitness. By reducing test duration, these protocols enhance patient comfort and compliance while maintaining diagnostic accuracy. Abbreviations Exercise testing : (ET) Electrocardiogram: (ECG) Heart rate: (HR) Metabolic equivalents (METs) Body Mass Index: (BMI) Maximum: (Max) Min: (Minute) Blood pressure: (BP) Sys: (Systolic) Dia: (Diastolic) Declarations Ethics approval and consent to participate: The stages of this research have been approved by the Ethics Committee of Mashhad University of Medical Sciences . Informed written consent to participate in the study was provided by all participants (or their parent or legal guardian in the case of children under 16). Ethics approval and consent to participate: This research project Accepted by MUMS research council, No: 4010918, and with Ethical approval no.IRMUMSREC.1401.302 Consent for publication: Not applicable. Funding: We would like to thank the Deputy of Research and Technology at MUMS institute for supporting the project. Financial support and sponsorship: We would like to thank the Deputy of Research and Technology at MUMS institute for supporting the project. References van der Cammen-van Zijp MH, Ijsselstijn H, Takken T, Willemsen SP, Tibboel D, Stam HJ, et al. Exercise testing of pre-school children using the Bruce treadmill protocol: new reference values. Eur J Appl Physiol. 2010;108(2):393-9. Garner KK, Pomeroy W, Arnold JJ. Exercise Stress Testing: Indications and Common Questions. Am Fam Physician. 2017;96(5):293-9. Paridon SM, Alpert BS, Boas SR, Cabrera ME, Caldarera LL, Daniels SR, et al. Clinical stress testing in the pediatric age group: a statement from the American Heart Association Council on Cardiovascular Disease in the Young, Committee on Atherosclerosis, Hypertension, and Obesity in Youth. Circulation. 2006;113(15):1905-20. Washington RL, Bricker JT, Alpert BS, Daniels SR, Deckelbaum RJ, Fisher EA, et al. Guidelines for exercise testing in the pediatric age group. From the Committee on Atherosclerosis and Hypertension in Children, Council on Cardiovascular Disease in the Young, the American Heart Association. Circulation. 1994;90(4):2166-79. Bruce RA, Kusumi F, Hosmer D. Maximal oxygen intake and nomographic assessment of functional aerobic impairment in cardiovascular disease. American heart journal. 1973;85(4):546-62. Gumming GR, Everatt D, Hastman L. Bruce treadmill test in children: normal values in a clinic population. The American journal of cardiology. 1978;41(1):69-75. Sarma S, Levine BD. Beyond the Bruce Protocol: Advanced Exercise Testing for the Sports Cardiologist. Cardiol Clin. 2016;34(4):603-8. Bires AM, Lawson D, Wasser TE, Raber-Baer D. Comparison of Bruce treadmill exercise test protocols: is ramped Bruce equal or superior to standard bruce in producing clinically valid studies for patients presenting for evaluation of cardiac ischemia or arrhythmia with body mass index equal to or greater than 30? J Nucl Med Technol. 2013;41(4):274-8. R. SSS. Treadmill Stress Testing Technique. Medscape; 2023. Vilcant V, Zeltser R. Treadmill stress testing. StatPearls [Internet]: StatPearls Publishing; 2023. Duff DK, De Souza AM, Human DG, Potts JE, Harris KC. A novel treadmill protocol for exercise testing in children: the British Columbia Children's Hospital protocol. BMJ Open Sport Exerc Med. 2017;3(1):e000197. Fagundes TTdS, Mizzaci CC, Buglia S, Wohnrath FdC, Medina F, França J, et al. Comparison between Bruce and ramp protocols for exercise testing in the diagnosis of myocardial ischemia. International Journal of Cardiovascular Sciences. 2021;35:28-36. Braden DS, Carroll JF. Normative cardiovascular responses to exercise in children. Pediatr Cardiol. 1999;20(1):4-10; discussion 1. Alvarez-Pitti J, Herceg-Čavrak V, Wójcik M, Radovanović D, Brzeziński M, Grabitz C, et al. Blood pressure response to exercise in children and adolescents. Front Cardiovasc Med. 2022;9:1004508. 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It effectively evaluates the adequacy of blood supply to the heart muscles through the coronary arteries and assesses overall heart function. The test is conducted in a controlled environment under the supervision of experienced medical personnel. During the test, technicians closely monitor the patient's heart rate, respiratory rate, blood pressure, heart rhythm, and fatigue level. The most common form of stress testing involves walking on a treadmill. If the initial test reveals abnormal heart function during exercise, additional diagnostic tools such as echocardiography or nuclear imaging may be utilized to refine the diagnosis(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough treadmill ET has some limitations, it remains a practical and user-friendly method, especially in pediatric populations, making it a preferred option for many physicians. One significant advantage of this method its versatility, as it can be used for patients of all ages, including children as young as three years old(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). However, greater attention must be given to safety considerations when testing young children(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThere is ongoing debate about the optimal methodology for exercise testing in children. Several protocols involving cycle ergometer or treadmill have been developed in this age group(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). The Bruce treadmill protocol, one of the most widely used standards, was initially introduced by Bruce et al.(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) for adults. Subsequently, Cumming et al. provided normative data on exercise responses and endurance times for 327 children aged 4 to 14 years(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). This protocol is now widely accepted for use in the pediatric population as well(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the Bruce protocol, patients progress through stages that require walking at increasingly faster speeds and steeper inclines. The standard protocol consists of seven stages, each lasting three minutes, but it can be extended to ten stages, although most patients do not complete all stages. The test begins at speed of 1.7 mph (2.7 km/h) and a 10% incline. At the end of each three-minute stage, both speed and incline are increased by approximately 1 mph and 2\u0026deg;, respectively(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). The Bruce protocol is applicable to all age groups, allowing for comparative data as a child grows(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Moreover, reference values for children are available(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDespite its utility, the Bruce protocol has some drawbacks. Its monotonous and physically demanding nature, combined with substantial workload increments, can make it tiresome and challenging for children, especially those with cardiac conditions or limited physical fitness. These factors necessitate frequent encouragement to ensure children complete the test(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe modified Bruce protocol offers an alternative with adding two lower workload warmup stages to the start of the standard Bruce protocol. These stages, each lasting three minutes, require less exertion than stage 1 of the standard protocol. The first stage involves walking at 1.7 mph with no incline (0%), and the second at 1.7 mph with a 5% incline. This modified protocol is particularly beneficial for individuals who are unable to perform vigorous exercise, including older adults and those with reduced exercise capacity due to cardiac conditions(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Because the many medical diagnostic tools, firstly designed for adult group, some of these methods are not suitable for children. Although modified Bruce protocol seems suitable, practical method for children but exam of better protocols with shorter duration ET can lead to better corporation of little child with same ET diagnostic goals(\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGiven the absence of a universally accepted protocol for pediatric exercise testing, we proposed shorter versions of the Bruce protocol lasting four and eight minutes. This study aimed to compare the sensitivity, characteristics, and accuracy of these shorter protocols with the standard 21-minute Bruce protocol, which is widely used in clinical practice. Additionally, the study evaluated and compared the hemodynamic responses, incidence of arrhythmias, and functional capacity across all three protocols.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design\u003c/h2\u003e \u003cp\u003eThis epidemiological analytical study aimed to evaluate and compare exercise stress testing protocols in pediatric patients. The design was inspired by the methodology outlined in a previous study by Thiago Teixeira da Silveira Fagundes(\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) This research project Accepted by MUMS research council, No: 4010918.\u003c/p\u003e \u003cp\u003e Informed written consent to participate in the study was provided by all participants (or their parent or legal guardian in the case of children\u003c/p\u003e \u003cp\u003eunder 16).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eParticipant Preparation\u003c/h3\u003e\n\u003cp\u003eParticipants were instructed to fast for several hours before the test to avoid discomfort or nausea, although small amounts of fluids were allowed. Caffeinated beverages, including coffee, tea, soda, and chocolate, were strictly prohibited. Before the test, a medical technician prepared the participants by applying electrodes to the skin for electrocardiogram (ECG) monitoring and fitting a blood pressure cuff on the arm.\u003c/p\u003e\n\u003ch3\u003eExercise Test Protocol\u003c/h3\u003e\n\u003cp\u003eThe exercise test began with a resting ECG, followed by a slow warm-up phase of two to three minutes on the treadmill. Participants gradually increased their speed and incline every two to three minutes until reaching their maximum capacity. Throughout the test, the supervising physician encouraged participants to continue until symptoms such as fatigue, dizziness, pain, or shortness of breath prompted termination.\u003c/p\u003e \u003cp\u003ePost-exercise, participants rested in a sitting or lying position for approximately 10 minutes, during which heart rate and blood pressure were closely monitored. Participants were also queried about their fatigue levels or any faintness. If the ECG indicated potential abnormalities, the test was terminated, and further examinations were conducted.\u003c/p\u003e\n\u003ch3\u003eProtocol Comparison\u003c/h3\u003e\n\u003cp\u003eThe study included three exercise protocols:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eStandard Bruce Protocol\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eModified 4-Minute Bruce Protocol\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eModified 8-Minute Bruce Protocol\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eTests were randomly assigned using a simple randomization software into two groups. After an 8\u0026ndash;12-minute recovery period, participants switched protocols, ensuring each group completed all three tests.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eOutcomes and Measurements\u003c/h3\u003e\n\u003cp\u003eThe primary measurable outcomes included:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eExercise duration (seconds)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eResting and maximum heart rate (HR, bpm)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eHR at the first minute of recovery\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eResting and maximum systolic arterial pressure (SAP, mmHg)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eMaximum double product (DP\u0026thinsp;=\u0026thinsp;HR \u0026times; SAP \u0026times; 10\u0026sup3;)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eWorkload in metabolic equivalents (METs)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eST-T changes, corrected QT interval (QTc), and arrhythmias\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eBlood pressure and clinical symptoms\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eInclusion and Exclusion Criteria\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003eInclusion Criteria:\u003c/h2\u003e \u003cp\u003eThe inclusion criteria for this study consisted of patients aged 5\u0026ndash;18 years who required further cardiac evaluation for one or more of the following conditions: chest pain accompanied by a positive family history, chest pain with active T wave changes during physical activity, suspected coronary abnormalities, or the need for an assessment of exercise capacity.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e\n\u003ch3\u003eExclusion Criteria:\u003c/h3\u003e\n\u003cp\u003eThe exclusion criteria included patients with atypical chest pain, unstable angina not controlled by medication, acute aortic dissection, acute myocarditis or pericarditis, significant and uncontrolled cardiac arrhythmias, severe symptomatic aortic stenosis, symptomatic and uncontrolled heart failure, respiratory conditions such as upper or lower respiratory diseases, or any blood, metabolic, or neurological disorders.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSample size and statistical analysis:\u003c/h2\u003e \u003cp\u003eBased on prior studies and the sensitivity of ECG in exercise testing, the sample size calculation was conducted using the formula for comparing two proportions. With an alpha level of 0.05, a beta level of 0.2, and proportion values of P1\u0026thinsp;=\u0026thinsp;0.55 and P2\u0026thinsp;=\u0026thinsp;0.78, the required sample size was determined to be 70 participants per group. Data were analyzed using SPSS version 24. Descriptive statistics included measures of central tendency, dispersion, and frequency percentages. Sensitivity, specificity, and diagnostic accuracy were calculated for each protocol. Paired t-tests were used for within-group comparisons, while unpaired t-tests assessed differences between groups. Receiver Operating Characteristic (ROC) curves were generated to compare the diagnostic performance of the protocols. A p-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003cp\u003e\u003cimg 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CCIAkhBEACQhiABIQhABkIQgAiAJQQRAEoIIgCQEEQBJCCIAkhBEACSp/XsiALojJjzwo0SBtuax6z/K0/X8NyG2TBnOAEhCEAGQhCACIAlBBEASggiAJAQRAEnGGkR0oyN9LBQuOzs7eYo/bm9vB/ZfXl7me9rj5OTk8fy1Pozy7+fXFpWD0f1ubbvW0az9/f1n9RBTTyjwu4aY5LrTutLZXf7tuX+3e//O63ZX9YuLi3zLy4rNo58HrYd3mPfpTvQ+lU1YBuHzuneYjznvWVYn/0pblL6qnromtkxrtbyYg4ZBRBRAbFvRxaZ9YQW+lJg8hkEjDCq+ouCo9H5+9Vr/ufb7QTdGzHnPstj8K11R2cbUU9fElulE5kRWV1fd48PDQ7axseHWff2LKF+bfura9oNhtri4mG/J3Lq2FXV73717l689OT4+zpaWlvJnf4aBZ2dn+bM/5ufn8zWMi4YramtF9xOOqScUm0gQubu7c49zc3PusYhVVtm8ii3h/MqkXV1duceii1xBsooCzfX19UCj/fz5c3Z6eurypv1qvIeHh/ne8dFci/5G0XyOPydTtMzCPM3R0VG2tbU1kK+y+Y6iekKJvEcSJSa5uoBKZ8MZdRP1vKx7rv11x/9Nqsqj5c+nvGpbzLxOWRfZjls2LKpSdd42pNRi5R3OxbRZVf6L2qHyXpb/rg9lpKpMTWM9EXUbFemXl5dLu5Dy8ePHRt51p1VZF1nbNSTSonIbN5V//wLK+oHjsbzfvHnjHrvg/v7ePfrt0Mq86NNBhjLxGgsiqpx+kHKLuoVF1LX++fNn/uyPaR/O2FyI3w22Ycyw4ZqUdZGVJ80baYik8tLFrnKYpC4MZ0Jl9cVQpp6JzIkU0ef0Kysrz+YWVHkWfIqWl+616HzVs7K5EdG7nC78qslQvWZtbS1/9kRj9devX+fPMpdHBeGy8XoT9A5dVN62lPUk28KCf1GvIwwmZfWEYi8SRBRAxP+kxiYV2+DLly9uMtRsbm4OPC+jLvKHDx/yZ08UgPzXqxErUFUFJcRTWfZ6PTd8NgcHB254F5ZzWT2hRP9dJlpVck1SKY0tRROm2uanGZb2JehcYmjSzc5dk3A+lYMWX79nUTqJJ37ZDUtXpuq8/eNrcjGsh7aLzYOf76I2V1VPXRJbpvyyWaCteexC3QzT9fw3IbZMX2xOBMBsIIgASEIQAZCEIAIgCUEEQBKCCIAkBBEASQgiAJIQRAAkIYgASEIQAZCEIAIgCUEEQBKCCIAkBBEASQgiAJLU/lEiAN0REx5qBREACDGcAZCEIAIgCUEEQBKCCIAkBBEASQgiABJk2f8BvIGRuNEGg6EAAAAASUVORK5CYII=\" width=\"273\" height=\"182\"\u003e\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe study included 76 pediatric patients aged 5\u0026ndash;17 years. Of these, 44 (57.9%) were male, and 32 (42.1%) were female. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows other demographic characteristics of the participants.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic characteristics of the participants\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWeight\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e32.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e19.47\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eStd. Deviation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMinimum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e11.83\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e74.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e32.65\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ePercentiles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e30.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e18.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e39.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e22.40\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe participants then performed the exercise test based on the standard Bruce protocol, as well as the 4-minute and 8-minute protocols. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the details of each of these protocols.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eProtocols characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProtocol\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean (\u0026plusmn; Std)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e4-min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEXCERCISE TIME (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e7.82 (\u0026plusmn; 0.40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Speed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6.78 (\u0026plusmn; 0.15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Incline (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e15.97 (\u0026plusmn; 0.23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e8-minute\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEXCERCISE TIME\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11.35 (\u0026plusmn;0.89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Speed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6.72 (\u0026plusmn; 0.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Incline\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e15.89 (\u0026plusmn; 0.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eBruce\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEXCERCISE TIME\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e15.81 (\u0026plusmn; 2.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e21.80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Speed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6.88 (\u0026plusmn; 0.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMax Incline\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e14.97 (\u0026plusmn; 0.85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAcross all protocols, heart rate (HR) and blood pressure (BP) values followed expected physiological patterns, with no statistically significant differences among the 4-minute, 8-minute, and standard Bruce protocols as shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChanges in HR\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProtocol\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMeasurement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean (\u0026plusmn; Std)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"10\" rowspan=\"11\"\u003e \u003cp\u003e4-minute\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRest HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e116.81 (\u0026plusmn; 18.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e187\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 1 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e125.34 (\u0026plusmn;18.21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e199\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 2 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e136.2 (\u0026plusmn;16.82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e188\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 3 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e155.28 (\u0026plusmn;25.89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e104\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e311\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 4 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e170.92 (\u0026plusmn;13.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e141\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e201\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 1 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e151.65 (\u0026plusmn;20.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e188\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 2 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e125.49 (\u0026plusmn;29.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e225\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 3 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e117.11 (\u0026plusmn; 21.19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e207\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e178.90 (\u0026plusmn;2.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e187\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget HR Percent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e100.68 (\u0026plusmn;12.48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e84.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e171.80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMETs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e13.55 (\u0026plusmn; 0.40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e13.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"10\" rowspan=\"11\"\u003e \u003cp\u003e8-minute\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRest HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e120.2 (\u0026plusmn;18.54)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e212\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 1 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e128.21 (\u0026plusmn;20.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e238\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 2 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e155.68 (\u0026plusmn;117.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1137\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 3 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e161.09 (\u0026plusmn; 23.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e117\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e292\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 4 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e176.35 (\u0026plusmn; 15.39)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e143\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e214\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 1 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e156.83 (\u0026plusmn; 24.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e206\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 2 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e133.12 (\u0026plusmn; 28.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e245\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 3 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e124.91 (\u0026plusmn; 22.69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e198\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e178.52 (\u0026plusmn;2.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e183\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget HR Percent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e103.97 (\u0026plusmn;14.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e170.20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMETs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e13.41 (\u0026plusmn; 0.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e13.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"10\" rowspan=\"11\"\u003e \u003cp\u003eBruce\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRest HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e110.4 (\u0026plusmn; 15.23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e137\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 1 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e123.33 (\u0026plusmn; 15.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e154\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 2 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e136.72 (\u0026plusmn; 17.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e179\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 3 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e158.17 (\u0026plusmn; 19.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e116\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStage 4 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e174.69 (\u0026plusmn; 15.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e135\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e204\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 1 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e153.43 (\u0026plusmn; 21.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e188\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 2 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e123.09 (\u0026plusmn; 18.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e155\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRecovery 3 HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e119.57 (\u0026plusmn; 18.51)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e176\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget HR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e177.97 (\u0026plusmn; 5.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e138\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e187\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget HR Percent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e102.39 (\u0026plusmn;9.49)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e78.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e137.40\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMETs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e13.17 (\u0026plusmn; 1.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15.80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChanges in BP\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProtocol\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMeasurement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean (\u0026plusmn; Std)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMin (mmHg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMax (mmHg)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e4-minute\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSYS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e102.61 (\u0026plusmn; 11.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e150\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e64.42 (\u0026plusmn;7.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHR BP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e10668.57 (\u0026plusmn;2261.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6400.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e17272.50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e8-minute\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSYS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e103.72 (\u0026plusmn;14.35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e155\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e65.85 (\u0026plusmn; 9.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHR BP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11187.83(\u0026plusmn;3162.96)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5550.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e23120.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eBruce\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSYS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e105.75 (\u0026plusmn;?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e160\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e66.64 (\u0026plusmn;?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e110\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHR BP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11820.50 (\u0026plusmn;?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7120.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22360.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAdditionally, changes in ST-T, clinical symptoms including weakness and chest pain, as well as the occurrence of arrhythmia in participants were examined, with the results presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical Symptoms and Arrhythmias Across Protocols\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eprotocol\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBruce\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 min\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4min\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eST-T changes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eweakness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.6%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.9%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.6%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChest pain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35.5%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36.6%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e31.4%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eArrythmia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe compared the qualitative variables with standard method B; In most cases, the variables had similar results in the three methods, and we checked the agreement between the two methods with Kappa statistics, which were significant (SIG\u0026thinsp;\u0026lt;\u0026thinsp;0.05) and its VALUE was closer to 1, which means they were in 100% agreement.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eExercise testing is a practical and user-friendly tool for evaluating children suspected of having cardiac conditions. When appropriate case selection is conducted, it provides valuable insights into cardiac hemodynamics and electrophysiological status.\u003c/p\u003e \u003cp\u003eThe purposes of exercise testing vary and may include assessing physical capacity, identifying structural heart disease, or diagnosing conduction abnormalities.\u003c/p\u003e \u003cp\u003eUnder normal conditions, an increasing heart rate is the primary indicator of rising cardiac output, with the maximum heart rate serving as a key measure of VO2 peak. in this study, there were no significant differences in results across three ET protocols, indicating that they yield comparable outcomes in terms of cardiac performance. Similarly, Braden et al found no significant differences between treadmill and cycle testing(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eBP is another critical variable in exercise testing, as both systolic and diastolic BP typically increase with advancing exercise stages. In our study, BP changes did not differ significantly among the Bruce protocol, 4-minute protocol, and 8-minute protocol. While some studies compare BP changes between treadmill and cycle ergometer tests, limited data exist regarding BP changes with varying treadmill test durations. Our findings suggest that peak BP can be achieved using shorter-duration protocols in children(\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMetabolic equivalents (METs) are also important in pediatric exercise testing, offering a practical means of quantifying the energy cost of activity. METs serve as indicators of functional capacity and aerobic power, though scores may vary based on fitness levels, the presence of cardiac disease, submaximal effort, and other factors. In this study, no significant differences were observed in METs scores across the three protocols, further supporting the validity of shorter-duration tests.\u003c/p\u003e \u003cp\u003eAdditionally, there were no significant differences in arrhythmia occurrence among the three protocols, demonstrating their equivalent sensitivity for detecting exercise-induced arrhythmias.\u003c/p\u003e \u003cp\u003eClinical symptoms and tolerance levels also showed no significant variation, confirming that all three protocols are similarly effective for evaluating physical activity tolerance and cardiac health.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study found no significant differences in clinical outcomes among the Bruce, 4-minute, and 8-minute protocols in children. Therefore, the shorter 4-minute and 8-minute protocols can be effectively used as alternatives to the standard Bruce method, with the added advantage of better cooperation from pediatric participants. Shorter-duration exercise test protocols are both feasible and accurate for achieving the goals of exercise testing. They are particularly beneficial for children with structural heart disease, systemic illnesses, or limited physical fitness. By reducing test duration, these protocols enhance patient comfort and compliance while maintaining diagnostic accuracy.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eExercise testing\u003cspan dir=\"RTL\"\u003e:\u003c/span\u003e (ET)\u003c/p\u003e\n\u003cp\u003eElectrocardiogram: (ECG)\u003c/p\u003e\n\u003cp\u003eHeart rate: (HR)\u003c/p\u003e\n\u003cp\u003eMetabolic equivalents (METs)\u003c/p\u003e\n\u003cp\u003eBody Mass Index: (BMI)\u003c/p\u003e\n\u003cp\u003eMaximum: (Max)\u003c/p\u003e\n\u003cp\u003eMin: (Minute)\u003c/p\u003e\n\u003cp\u003eBlood pressure: (BP)\u003c/p\u003e\n\u003cp\u003eSys: (Systolic)\u003c/p\u003e\n\u003cp\u003eDia: (Diastolic)\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e Ethics approval and consent to participate:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe stages of this research have been approved by the Ethics Committee of Mashhad University of Medical Sciences\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInformed written consent to participate in the study was provided by all participants (or their parent or legal guardian in the case of children\u003cbr\u003e under 16).\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n\u003cli\u003eEthics approval and consent to participate: This research project Accepted by MUMS research council, No: 4010918, and with Ethical approval no.IRMUMSREC.1401.302\u003c/li\u003e\n\u003cli\u003eConsent for publication: Not applicable.\u003c/li\u003e\n\u003cli\u003eFunding: We would like to thank the Deputy of Research and Technology at MUMS institute for supporting the project.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFinancial support and sponsorship:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank the Deputy of Research and Technology at MUMS institute for supporting the project.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003evan der Cammen-van Zijp MH, Ijsselstijn H, Takken T, Willemsen SP, Tibboel D, Stam HJ, et al. Exercise testing of pre-school children using the Bruce treadmill protocol: new reference values. Eur J Appl Physiol. 2010;108(2):393-9.\u003c/li\u003e\n\u003cli\u003eGarner KK, Pomeroy W, Arnold JJ. Exercise Stress Testing: Indications and Common Questions. Am Fam Physician. 2017;96(5):293-9.\u003c/li\u003e\n\u003cli\u003eParidon SM, Alpert BS, Boas SR, Cabrera ME, Caldarera LL, Daniels SR, et al. Clinical stress testing in the pediatric age group: a statement from the American Heart Association Council on Cardiovascular Disease in the Young, Committee on Atherosclerosis, Hypertension, and Obesity in Youth. Circulation. 2006;113(15):1905-20.\u003c/li\u003e\n\u003cli\u003eWashington RL, Bricker JT, Alpert BS, Daniels SR, Deckelbaum RJ, Fisher EA, et al. Guidelines for exercise testing in the pediatric age group. From the Committee on Atherosclerosis and Hypertension in Children, Council on Cardiovascular Disease in the Young, the American Heart Association. Circulation. 1994;90(4):2166-79.\u003c/li\u003e\n\u003cli\u003eBruce RA, Kusumi F, Hosmer D. Maximal oxygen intake and nomographic assessment of functional aerobic impairment in cardiovascular disease. American heart journal. 1973;85(4):546-62.\u003c/li\u003e\n\u003cli\u003eGumming GR, Everatt D, Hastman L. Bruce treadmill test in children: normal values in a clinic population. The American journal of cardiology. 1978;41(1):69-75.\u003c/li\u003e\n\u003cli\u003eSarma S, Levine BD. Beyond the Bruce Protocol: Advanced Exercise Testing for the Sports Cardiologist. Cardiol Clin. 2016;34(4):603-8.\u003c/li\u003e\n\u003cli\u003eBires AM, Lawson D, Wasser TE, Raber-Baer D. Comparison of Bruce treadmill exercise test protocols: is ramped Bruce equal or superior to standard bruce in producing clinically valid studies for patients presenting for evaluation of cardiac ischemia or arrhythmia with body mass index equal to or greater than 30? J Nucl Med Technol. 2013;41(4):274-8.\u003c/li\u003e\n\u003cli\u003eR. SSS. Treadmill Stress Testing Technique. Medscape; 2023.\u003c/li\u003e\n\u003cli\u003eVilcant V, Zeltser R. Treadmill stress testing. StatPearls [Internet]: StatPearls Publishing; 2023.\u003c/li\u003e\n\u003cli\u003eDuff DK, De Souza AM, Human DG, Potts JE, Harris KC. A novel treadmill protocol for exercise testing in children: the British Columbia Children\u0026apos;s Hospital protocol. BMJ Open Sport Exerc Med. 2017;3(1):e000197.\u003c/li\u003e\n\u003cli\u003eFagundes TTdS, Mizzaci CC, Buglia S, Wohnrath FdC, Medina F, Fran\u0026ccedil;a J, et al. Comparison between Bruce and ramp protocols for exercise testing in the diagnosis of myocardial ischemia. International Journal of Cardiovascular Sciences. 2021;35:28-36.\u003c/li\u003e\n\u003cli\u003eBraden DS, Carroll JF. Normative cardiovascular responses to exercise in children. Pediatr Cardiol. 1999;20(1):4-10; discussion 1.\u003c/li\u003e\n\u003cli\u003eAlvarez-Pitti J, Herceg-Čavrak V, W\u0026oacute;jcik M, Radovanović D, Brzeziński M, Grabitz C, et al. Blood pressure response to exercise in children and adolescents. Front Cardiovasc Med. 2022;9:1004508.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Exercise test, treadmill, ECG, heart rate, arrhythmia","lastPublishedDoi":"10.21203/rs.3.rs-6715310/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6715310/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eExercise testing is widely used to assess functional capacity and detect cardiac abnormalities in pediatrics. The standard Bruce protocol, though effective, is lengthy and can challenge compliance, especially in children.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eThis study evaluates the diagnostic value of the modified 4-minute and 8-minute exercise test protocols compared to the standard 21-minute Bruce protocol in terms of sensitivity, specificity, accuracy, and tolerance among children.\u003c/p\u003e\u003ch2\u003eMaterials \u0026amp; Methods\u003c/h2\u003e \u003cp\u003eIn this epidemiological analytical study 76 children under the age of 18 who had an indication for exercise testing were recruited. The study included three exercise protocols: standard Bruce protocol, modified 4-minute Bruce protocol, and modified 8-minute Bruce protocol. Tests were randomly assigned using a simple randomization software into two groups. After an 8\u0026ndash;12-minute recovery period, participants switched protocols, ensuring each group completed all three tests. Data were analyzed using SPSS version 24. Descriptive statistics included measures of central tendency, dispersion, and frequency percentages. Sensitivity, specificity, and diagnostic accuracy were calculated for each protocol. Paired t-tests were used for within-group comparisons, while unpaired t-tests assessed differences between groups.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eIn this study, 76 patients, 44 boys and 32 girls, were examined. The age of the children varied from 5 to 17 years; we compared the qualitative variables with the standard B method; In most cases, the variables had similar results in the three methods, and we checked the agreement between the two methods with Kappa statistics, which were significant (SIG\u0026thinsp;\u0026lt;\u0026thinsp;0.05) and its VALUE was closer to 1, which means they were in 100% agreement.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis study found no significant differences in clinical outcomes among the Bruce, 4-minute, and 8-minute protocols in children. Therefore, the shorter 4-minute and 8-minute protocols can be effectively used as alternatives to the standard Bruce method.\u003c/p\u003e","manuscriptTitle":"Investigating and Comparing the Diagnostic Value of Exercise Test Protocols in Pediatrics: A Shorter Alternative to the Bruce Method","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-03 08:24:21","doi":"10.21203/rs.3.rs-6715310/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c77c19b9-2733-4f77-9259-8386ffb40b95","owner":[],"postedDate":"July 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-25T13:27:48+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-03 08:24:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6715310","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6715310","identity":"rs-6715310","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}