A Randomized Controlled Trial to Investigate the Effects of Balneotherapy on Cardiac Autonomic Regulation and Exercise Performance in Healthy Adolescents Undergoing Real 1600-meter Altitude Training and Athlete Training.
| Registry | NCT07608887 |
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| Status | Completed |
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| Phase | Not applicable |
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| Study type | Interventional; randomized, parallel, masking: single, treatment |
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| Enrollment | 27 (Actual) |
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| Sponsor | Macao Polytechnic University (Other) |
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| Conditions | Altitude Training Adaptation, Autonomic Nervous System, Hydrotherapy, Exercise Performance, Altitude Sickness |
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| Interventions | Control Group：Natural Recovery, Hot water immersion group, hot spring immersion group (Behavioral) |
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| Dates | start 2026-01-10, primary completion 2026-03-07, completion 2026-03-08, first posted 2026-05-27, last updated 2026-06-26 |
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| Locations | 1 site in China |
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Related Papers Related Patents Related Grants Related Experts
All trials for Altitude Training Adaptation All trials for Autonomic Nervous System All trials of Control Group：Natural Recovery All trials of Hot water immersion group
-Summary
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.
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+Arms and interventions
| Arm | Type | Interventions | Description |
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| Natural Recovery Group | Active comparator | Behavioral: Control Group：Natural Recovery | 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. |
| Hot water immersion group | Active comparator | Behavioral: Hot water immersion group | 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. |
| Hot Spring Immersion Group | Experimental | Behavioral: hot spring 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. |
- Control Group：Natural Recovery (Behavioral), also known as NR: 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.
- Hot water immersion group (Behavioral), also known as HWI: 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.
- hot spring immersion group (Behavioral), also known as HSI: 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.
+Outcome measures
Primary outcomes
- Heart Rate Variability (HRV) - RMSSD [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.]: 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).
Secondary outcomes
- HRV - SDNN [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.]: 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
- Peripheral Oxygen Saturation (SpO2) [one month.]: Resting peripheral oxygen saturation measured via fingertip pulse oximeter after 10 minutes of seated rest. Unit: percentage (%)
- Rating of Perceived Exertion (RPE) [one month.]: 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
- Maximum oxygen uptake [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.]: 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.
- 30-second anaerobic power. [The tests are scheduled before entering the plateau (baseline), during the 4th week of plateau training, and 1 week after leaving the plateau.]: 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.
+Eligibility
Sex: All, ages: 11 Years to 17 Years, accepts healthy volunteers
Inclusion Criteria:
* Male or female aged 11-17years
* Regular endurance training (≥3 sessions/week) for ≥2 years
* No history of altitude exposure >2000m in the past 3 months
* No contraindications to hot water immersion (e.g., uncontrolled hypertension, severe cardiovascular disease, open wounds, pregnancy)
* Ability to provide written informed consent- Willingness to abstain from other recovery modalities (e.g., massage, cryotherapy, compression garments) during the study period
Exclusion Criteria:
* History of cardiovascular, respiratory, renal, or endocrine disorders
* Current use of medications affecting autonomic function (e.g., beta-blockers, anticholinergics)- History of syncope or heat intolerance
* Acute musculoskeletal injury within the past 6 months- Regular use of sauna, hot tub, or spa within the past month
* Pregnancy or breastfeeding (for female participants)- Shift work or trans-meridian travel within 2 weeks prior to baseline assessment
* Alcohol consumption >14 units/week or smoking
+Locations (1)
| Facility | City | Country | Status |
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| Macao Polytechnic University | Macao | China | |
+Publications
- Stanley J, Peake JM, Buchheit M. Consecutive days of cold water immersion: effects on cycling performance and heart rate variability. Eur J Appl Physiol. 2013 Feb;113(2):371-84. doi: 10.1007/s00421-012-2445-2. Epub 2012 Jul 3. PMID 22752345
- Jdidi H, Dugue B, de Bisschop C, Dupuy O, Douzi W. The effects of cold exposure (cold water immersion, whole- and partial- body cryostimulation) on cardiovascular and cardiac autonomic control responses in healthy individuals: A systematic review, meta-analysis and meta-regression. J Therm Biol. 2024 Apr;121:103857. doi: 10.1016/j.jtherbio.2024.103857. Epub 2024 Apr 18. PMID 38663342
- Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med. 2015 Apr;175(4):542-8. doi: 10.1001/jamainternmed.2014.8187. PMID 25705824
- Michalsen A, Ludtke R, Buhring M, Spahn G, Langhorst J, Dobos GJ. Thermal hydrotherapy improves quality of life and hemodynamic function in patients with chronic heart failure. Am Heart J. 2003 Oct;146(4):728-33. doi: 10.1016/S0002-8703(03)00314-4. PMID 14564334
- Buchheit M, Simpson BM, Garvican-Lewis LA, Hammond K, Kley M, Schmidt WF, Aughey RJ, Soria R, Sargent C, Roach GD, Claros JC, Wachsmuth N, Gore CJ, Bourdon PC. Wellness, fatigue and physical performance acclimatisation to a 2-week soccer camp at 3600 m (ISA3600). Br J Sports Med. 2013 Dec;47 Suppl 1(Suppl 1):i100-6. doi: 10.1136/bjsports-2013-092749. PMID 24282195