Altitude Training AdaptationNCT07608887
Effect of Hot Spring Therapy on Autonomic Nervous System and Exercise Performance During Altitude Training
A study testing Hot water immersion group and hot spring immersion group in people with Altitude Training Adaptation and Autonomic Nervous System, run by Macao Polytechnic University at 1 site in China.
Trial 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. Read more about this study
- Who is it for?
- Ages 11 to 17 yearsHealthy volunteers can take part
- Conditions the study is for
- Altitude Training Adaptation, Autonomic Nervous System, Hydrotherapy
- What is being tested?
- Hot water immersion group and hot spring immersion group
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 27 participants
- Where
- 1 siteChina
- Study dates
- 10 Jan 2026to 8 Mar 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 11 to 17 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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.
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.
- Conditions
- Altitude Training Adaptation, Autonomic Nervous System, Hydrotherapy, Exercise Performance, Altitude Sickness
- Being tested
- Control Group：Natural Recovery, Hot water immersion group, hot spring immersion group
- Keywords
- Autonomic Nervous System, hysical Performance, Hydrotherapy, Hot Springs
- Medical subject headings
- Altitude Sickness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Control Group：Natural RecoveryBehavioural
Also called 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 groupBehavioural
Also called 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 groupBehavioural
Also called 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.
| Study group | Role | What they receive |
|---|---|---|
| Natural Recovery Group | Active comparator | 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. Receives: Behavioral: Control Group：Natural Recovery |
| Hot water immersion group | Active comparator | 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. Receives: Behavioral: Hot water immersion group |
| Hot Spring Immersion Group | Experimental | 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. Receives: Behavioral: hot spring immersion group |
What is being measured
The primary outcome is the main question the study is designed to answer.
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).
Measured: 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.
Secondary outcomes (5)
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
Measured: 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 (%)
Measured: 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
Measured: 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.
Measured: 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.
Measured: The tests are scheduled before entering the plateau (baseline), during the 4th week of plateau training, and 1 week after leaving the plateau.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 May 2026
- Study start10 Jan 2026
- Primary completion7 Mar 2026
- Study completion8 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Altitude Training AdaptationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 27 participants (actual)
Sponsor and investigators
- Lead sponsor
- Macao Polytechnic University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ziyue Ou, Macao Polytechnic University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07608887
- Sponsor's protocol ID
- 202502AS100005
- Status last verified
- Jan 2026
- First submitted
- 14 May 2026
- Last updated
- 26 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- 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.
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.
PubMed 22752345Jdidi 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.
PubMed 38663342Laukkanen 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.
PubMed 25705824Michalsen 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.
PubMed 14564334Buchheit 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.
PubMed 24282195
Study at a glance
From the registry record, last updated by the sponsor on 26 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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.
- ClinicalTrials.gov ID
- NCT07608887
- Acronym / sponsor ID
- 202502AS100005
- Conditions
- Altitude Training Adaptation, Autonomic Nervous System, Hydrotherapy, Exercise Performance, Altitude Sickness
- Keywords
- Autonomic Nervous System, hysical Performance, Hydrotherapy, Hot Springs
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 27 participants (actual)
- Lead sponsor
- Macao Polytechnic UniversityUniversity, hospital or other
- Study start
- 10 Jan 2026 (actual)
- Primary completion
- 7 Mar 2026 (actual)
- Study completion
- 8 Mar 2026 (actual)
- First posted
- 27 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Natural Recovery Group | Active comparator | Behavioral: Control Group：Natural RecoveryControl 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 groupThe 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 groupThe 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. |
Who may qualify
- Ages
- 11 to 17 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Control Group：Natural RecoveryAlso: NRControl 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. | Behavioural | Natural Recovery Group |
| Hot water immersion groupAlso: HWIThe 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. | Behavioural | Hot water immersion group |
| hot spring immersion groupAlso: HSIThe 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. | Behavioural | Hot Spring Immersion Group |
Primary outcome
Heart Rate Variability (HRV) - RMSSD
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.
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).
5 secondary outcomes
HRV - SDNN
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)
Time frame: one month.
Rating of Perceived Exertion (RPE)
Time frame: one month.
Maximum oxygen uptake
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.
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.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Jun 2026.
- Background: PubMed 22752345Stanley 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.
- Background: PubMed 38663342Jdidi 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.
- Background: PubMed 25705824Laukkanen 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.
- Background: PubMed 14564334Michalsen 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.
- Background: PubMed 24282195Buchheit 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.
- Individual participant dataSharing planned: 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Hot water immersion group and hot spring immersion group in people with Altitude Training Adaptation and Autonomic Nervous System, run by Macao Polytechnic University at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Heart Rate Variability (HRV) - RMSSD (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.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07608887, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Jun 2026.