Effect of Hot Spring Therapy on Autonomic Nervous System and Exercise Performance During Altitude Training
A Randomized Controlled Trial Investigating the Effects of Balneotherapy on Cardiac Autonomic Modulation and Athletic Performance in Healthy Adults Undergoing Simulated Altitude Training Undergoing Simulated Athlete Training
1 other identifier
interventional
27
1 country
1
Brief 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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at below P25 for not_applicable
Started May 2026
Shorter than P25 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
May 14, 2026
CompletedStudy Start
First participant enrolled
May 25, 2026
CompletedFirst Posted
Study publicly available on registry
May 27, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 25, 2026
ExpectedStudy Completion
Last participant's last visit for all outcomes
June 25, 2026
May 27, 2026
January 1, 2026
1 month
May 14, 2026
May 19, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (2)
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).
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.
1000-meter ergometer test.
Perform a 1000-meter all-out test on a rowing ergometer. Protocol: sprint at maximum effort to measure the shortest time. Record time. Units: seconds. Baseline, Week 3, Week 4.
Baseline measurements were taken before the official start of the experiment and during the 3rd and 4th weeks after ascending to the plateau.
Secondary Outcomes (3)
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.
Peripheral Oxygen Saturation (SpO2)
one month.
Rating of Perceived Exertion (RPE)
one month.
Study Arms (3)
Natural Recovery Group
ACTIVE COMPARATORControl 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 COMPARATORThe 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 includes whole-body immersion up to the neck for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Hot Spring Immersion Group
EXPERIMENTALThe 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 includes whole-body immersion to the neck for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Interventions
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.
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 includes whole-body immersion up to the neck for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
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 includes whole-body immersion to the neck for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Eligibility Criteria
You may qualify if:
- 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
You may not qualify if:
- 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
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Macao Polytechnic University
Macao, China
Related Publications (5)
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: 22752345BACKGROUNDJdidi 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: 38663342BACKGROUNDLaukkanen 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: 25705824BACKGROUNDMichalsen 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: 14564334BACKGROUNDBuchheit 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: 24282195BACKGROUND
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- SINGLE
- Who Masked
- PARTICIPANT
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Principal Investigator
Study Record Dates
First Submitted
May 14, 2026
First Posted
May 27, 2026
Study Start
May 25, 2026
Primary Completion (Estimated)
June 25, 2026
Study Completion (Estimated)
June 25, 2026
Last Updated
May 27, 2026
Record last verified: 2026-01