An interventional study of Control Group：Natural Recovery and Hot water immersion group in Altitude Training Adaptation, Autonomic Nervous System and Hydrotherapy, sponsored by Macao Polytechnic University. Completed at 1 site in China. Open to participants aged 11 Years to 17 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-26.
Sponsored by Macao Polytechnic University · Not applicable, Interventional, and Treatment
This randomized controlled trial aims to investigate the effects of balneotherapy (hot spring bathing) on cardiac autonomic nervous system function and exercise performance in healthy athletes undergoing high-altitude training. Participants will be randomly assigned to the intervention group (receiving hot spring baths three times per week (38°C, 20 minutes) combined with high-altitude training), the control group (receiving routine recovery protocols combined with high-altitude training), or the hot water immersion group (receiving hot water baths three times per week (38°C, 20 minutes) combined with high-altitude training). Primary outcome measures include heart rate variability (HRV) indices and exercise performance indicators. Secondary outcomes include blood lactate, peripheral oxygen saturation (SpO2), and subjective fatigue. These findings may provide evidence for non-pharmacological interventions to enhance high-altitude training adaptation and exercise recovery.
189 studies on the registry are indexed under Altitude Sickness; 44 are open to participants now.
This study's enrollment of 27 is below the median of 33 across 157 interventional studies indexed under Altitude Sickness.
Browse Altitude Sickness studies →Macao Polytechnic University is the lead sponsor of 8 studies on the registry; 3 are open to participants now.
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Exclusion Criteria:
Control group participants will undergo the same altitude training protocol (altitude 1600 meters) for 4 weeks. After each training session, participants will receive standard recovery procedures, including 20 minutes of passive rest in a thermoneutral environment (room temperature 24°C), supplemented with mild hydration and self-selected stretching. No hydrothermal intervention will be provided.
Behavioral: Control Group：Natural Recovery
The hot water immersion group will undergo a 4-week altitude training at 1600 meters above sea level. Subjects will receive a 20-minute hot water immersion (daily tap water, 38°C±1°C) in a standardized indoor hot spring facility. The immersion protocol involves soaking the body below the chest for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Behavioral: Hot water immersion group
The hot spring immersion group will undergo a 4-week high-altitude training at an altitude of 1600 meters. Subjects will receive a 20-minute hot spring therapy (natural hot spring water, 38°C ± 1°C) in a standardized indoor hot spring facility. The immersion protocol involves soaking the body below the chest for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Behavioral: hot spring immersion group
Control group participants will undergo the same altitude training protocol (altitude 1600 meters) for 4 weeks. After each training session, participants will receive standard recovery procedures, including 20 minutes of passive rest in a thermoneutral environment (room temperature 24°C), supplemented with mild hydration and self-selected stretching. No hydrothermal intervention will be provided.
Also known as: NR
The hot water immersion group will undergo a 4-week altitude training at 1600 meters above sea level. Subjects will receive a 20-minute hot water immersion (daily tap water, 38°C±1°C) in a standardized indoor hot spring facility. The immersion protocol involves soaking the body below the chest for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Also known as: HWI
The hot spring immersion group will undergo a 4-week high-altitude training at an altitude of 1600 meters. Subjects will receive a 20-minute hot spring therapy (natural hot spring water, 38°C ± 1°C) in a standardized indoor hot spring facility. The immersion protocol involves soaking the body below the chest for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Also known as: HSI
Heart Rate Variability (HRV) - RMSSD
Root mean square of successive differences (RMSSD) between normal heartbeats, measured from a 5-minute seated ECG recording in a quiet, temperature-controlled (22-24°C) room after 15 minutes of rest. A higher RMSSD value indicates stronger parasympathetic activity. Unit: milliseconds (ms). Baseline, Week 2, Week 3 (post-intervention).
Time frame: Baselines were measured at the formal start of the experiment, at night during the 2nd, 3rd, and 4th weeks (post-intervention) after ascending the plateau, and post-tests were conducted one week after descending the plateau.
HRV - SDNN
Standard deviation of NN intervals (normal-to-normal R-R intervals), reflecting overall autonomic modulation. Unit: milliseconds (ms). Baseline, Week 2, Week 3, Week4, post-tests
Time frame: Baselines were measured at the formal start of the experiment, at night during the 2nd, 3rd, and 4th weeks (post-intervention) after ascending the plateau, and post-tests were conducted one week after descending the plateau.
Peripheral Oxygen Saturation (SpO2)
Resting peripheral oxygen saturation measured via fingertip pulse oximeter after 10 minutes of seated rest. Unit: percentage (%)
Time frame: one month.
Rating of Perceived Exertion (RPE)
Borg 6-20 scale rating of perceived exertion recorded immediately after each training session. Higher scores indicate greater subjective effort. Unit: score (6-20). Daily during intervention
Time frame: one month.
Maximum oxygen uptake
Testing maximum oxygen uptake on a rowing ergometer combined with a cardiopulmonary function tester. Protocol: Using a graded incremental protocol to test maximal oxygen uptake (VO2max). Units: mL·kg-1 ·min-1. Baseline, Week 5.
Time frame: The baseline measurement was taken before the official start of the experiment, and the post-test was conducted one week after descending from the plateau.
30-second anaerobic power.
Perform a 30-s all-out test on a rowing ergometer. Protocol: sprint at maximum effort to measure the 30-second average power. Record power. Units: watt. Baseline, Week 4，1 week after altitude training.
Time frame: The tests are scheduled before entering the plateau (baseline), during the 4th week of plateau training, and 1 week after leaving the plateau.
Plan to share: Undecided — The current research project has not yet been completed, and the data have not been publicly released. After publication, sharing will be decided on a case-by-case basis.
This study is completed, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Macao Polytechnic University