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Central FatigueHSCF-AHTNCT07615478

Effect of Hot Spring Therapy on Central Fatigue Elimination During Altitude Training

A study testing Natural recovery, Hot water immersion and Hot spring balneotherapy in people with Central Fatigue and Altitude Training, run by Macao Polytechnic University at 1 site in China.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

This randomized controlled trial investigates the effects of hot spring balneotherapy on central fatigue elimination in adolescent rowers undergoing altitude training at approximately 1600 meters (Tengchong, Yunnan). Read more about this study

Who is it for?
Ages 12 to 16 yearsHealthy volunteers can take part
What is being tested?
Natural recovery, Hot water immersion and Hot spring balneotherapy
Could I receive a placebo?
No, everyone receives an active treatment
How many people
27 participants
Where
1 siteChina
Study dates
25 May 2026to 25 Jun 2026
Phase
Interventional
Are there results?
Not yet: the study is under way

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 12 to 16 years
  • All sexes
  • Healthy volunteers accepted
  • Child

Who may be able to join

  • Male or female aged 12-16 years- Healthy with no serious chronic diseases or skin conditions
  • At least 1 year of systematic rowing training experience
  • Currently undergoing centralized altitude training at approximately 1600 meters- No history of systematic hot spring or spa immersion within the past month
  • No allergy history to sodium bicarbonate or hot spring minerals- Ability to provide written informed assent (participant) and written informed consent (parent/guardian)- No acute infection, fracture, or surgery within the past month
  • Not currently taking non-steroidal anti-inflammatory drugs (NSAIDs), immunosuppressants, or medications affecting autonomic or cognitive function

Who cannot join

  • History of cardiovascular, respiratory, renal, endocrine, or neurological disorders- Uncontrolled hypertension or hypotension
  • History of syncope, heat intolerance, or severe dizziness during hot water immersion- Open wounds, severe eczema, or other skin conditions contraindicating water immersion
  • Current use of beta-blockers, anticholinergics, stimulants, sedatives, or other medications affecting central nervous system function
  • Color blindness or uncorrected visual impairment affecting Stroop test performance- Pregnancy (for female participants)- Alcohol consumption or smoking
  • Shift work or trans-meridian travel within 2 weeks prior to baseline assessment
  • Any condition deemed by the investigator as unsafe for participation

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Ziyue Ou, PHD contact

+8615626121623

p2521734@mpu.edu.mo

China1 site, 1 recruiting

  • Macao Polytechnic University

    Macao, Macao

    Ziyue Ou, PHD, +8615626121623, p2521734@mpu.edu.mo

    Ziyue Ou, 15626121623, 105852022100090@stu.gzsport.edu.cn

    Recruiting

Other trials in China

About this study

Official title: A Randomized Controlled Trial Investigating the Effects of Hot Spring Therapy Balneotherapy on Central Activation, Cognitive Function, and Exercise Performance in Adolescent Rowers During Altitude Training

This randomized controlled trial investigates the effects of hot spring balneotherapy on central fatigue elimination in adolescent rowers undergoing altitude training at approximately 1600 meters (Tengchong, Yunnan). Thirty adolescent athletes (aged 12-16 years) will be stratified by sex and randomly allocated to three groups: Group A (natural recovery, no immersion), Group B (38°C pure water immersion), and Group C (38°C sodium bicarbonate hot spring immersion). Interventions will be administered 3 times per week for 4 weeks. The primary outcomes are central fatigue indices including voluntary activation (VA) and central activation ratio (CAR). Secondary outcomes encompass cognitive function (Stroop test, Psychomotor Vigilance Test), cerebral hemodynamics (functional near-infrared spectroscopy, transcranial Doppler ultrasound), exercise performance (maximal oxygen uptake, 1000m test, 500m test), blood lactate, and hematological parameters (white blood cells, neutrophils, platelets).

Read the detailed description

Altitude training induces central fatigue characterized by decreased descending neural drive from the brain to skeletal muscle, reduced voluntary activation, and impaired cognitive function. This study employs a stratified randomized block design to evaluate whether post-exercise hot spring immersion can accelerate central fatigue recovery compared to pure warm water immersion and natural recovery. All participants will undergo standardized rowing training at approximately 1600 meters altitude. Group C will receive immersion in natural hot spring water at 38°C for 20 minutes. Group B will receive immersion in pure water at the same temperature and duration as a thermal control. Group A will undergo standard training recovery without immersion. The study incorporates partial blinding: Groups B and C are single-blinded to participants (identical appearance and protocol); Group A serves as an open-label control. Assessments will be conducted at baseline (pre-altitude), mid-intervention (Week 2), end-intervention (Week 4), and follow-up (1-2 weeks post-altitude).

Being tested
Natural recovery, Hot water immersion, Hot spring balneotherapy
Keywords
Altitude Sickness, Cognition, Hydrotherapy, Hot Springs, Athletic Performance
Medical subject headings
Cognitive Dysfunction, Altitude Sickness

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Natural recoveryBehavioural

    Also called NR

    Standard post-exercise recovery without water immersion. Participants rest passively in a thermoneutral environment (24°C, 50-60% humidity) for 20 minutes with ad libitum water and optional self-directed stretching. No heat, cold, or hydrotherapy interventions are applied.

  • Hot water immersionBehavioural

    Also called HWI

    After exercise, full-body immersion in daily tap water. Temperature: 38°C ± 0.5°C. Duration: 20 minutes per session, 3 times per week (Tuesday, Thursday, Saturday at 16:00), for 4 consecutive weeks (total of 12 sessions). Protocol: Full-body immersion below the neck for 20 minutes, followed by a 10-minute rest before leaving the facility.

  • Hot spring balneotherapyBehavioural

    Also called HSB

    After exercise, full-body immersion in natural hot spring water (pH approx. 7.4, Na+ 1210 mg/L, HCO3- approx. 3300 mg/L, total dissolved solids >1000 mg/L). Temperature: 38°C ± 0.5°C. Duration: 20 minutes per session, 3 times per week (Tuesday, Thursday, Saturday at 16:00), for 4 consecutive weeks (12 sessions total). Protocol: Full-body immersion below the neck for 20 minutes, followed by a 10-minute rest before leaving the facility.

Study groups in NCT07615478
Study groupRoleWhat they receive
Natural Recovery GroupActive comparatorParticipants in Group A will undergo standardized rowing training at approximately 1600 meters altitude for 4 weeks. After each training session, participants will receive standard training recovery procedures without any water immersion intervention. Recovery includes passive rest, self-directed light stretching, and ad libitum hydration in a thermoneutral environment (room temperature 24°C) for 20 minutes. No thermal or hydrotherapy intervention will be provided.
Receives: Behavioral: Natural recovery
Hot water immersion groupActive comparatorSubjects in Group B will undergo the same standardized rowing training at an altitude of approximately 1600 meters for 4 weeks. After each training session, subjects will receive whole-body immersion (below the neck, with the head above water) in daily tap water at 38°C ± 0.5°C for 20 minutes. The water temperature is monitored by a precision thermometer with an error of ≤ ±0.5°C. The immersion is conducted in a standardized indoor facility, and the time is 16:00 on Tuesday, Thursday, and Saturday.
Receives: Behavioral: Hot water immersion
Hot Spring Immersion GroupExperimentalParticipants in Group C will undergo the same standardized rowing training at approximately 1600 meters altitude for 4 weeks. After each training session, participants will receive full-body immersion (below neck, head above water) in natural hot spring water at 38°C ± 0.5°C for 20 minutes. The spring water has a pH of approximately 7.4, Na+ content of 1210 mg/L, and HCO3- content of approximately 3300 mg/L. Immersion will be performed in a standardized indoor facility on Tuesday, Thursday, and Saturday at 16:00, using the same protocol as Group B to maintain blinding.
Receives: Behavioral: Hot spring balneotherapy

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Voluntary Activation

    Voluntary activation assessed by the interpolated twitch technique (ITT) during maximal voluntary contraction (MVC) of the quadriceps femoris using percutaneous electrical stimulation. A single stimulus is superimposed on MVC; VA is calculated as: VA = (1 - superimposed twitch force / potentiated resting doublet force) × 100%. Higher VA indicates greater central neural drive. Unit: percentage (%).

    Measured: Baseline (Week 0), Week 2, Week 3, Week 4 (post-intervention), Follow-up (Week 1-2 post-altitude)

  2. Central Activation Ratio

    Central activation ratio measured as the ratio of maximal voluntary contraction force to the force evoked by supramaximal electrical stimulation of the femoral nerve during quadriceps contraction. CAR = MVC force / (MVC force + superimposed twitch force). Values closer to 1.0 indicate less central fatigue. Unit: ratio (0-1, no units).

    Measured: Baseline (Week 0), Week 2, Week 3, Week 4, Follow-up (Week 5-6 post-altitude)

Secondary outcomes (6)

  1. Stroop Test Performance

    Computerized Stroop Color-Word Test measuring executive function and cognitive inhibition. Outcome variables: reaction time (ms) for congruent and incongruent trials, with interference effect calculated as incongruent minus congruent reaction time. Administered in a quiet, temperature-controlled room (22-24°C). Unit: milliseconds (ms).

    Measured: Baseline, Week 2,Week 4, Follow-up (Week 1-2 post-altitude)

  2. Cerebral Oxygenation

    Changes in oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) in the prefrontal cortex during rest and cognitive tasks, measured by functional near-infrared spectroscopy (fNIRS) with a multichannel system. Outcome: relative concentration changes (ΔμM) in HbO2 and Hb from baseline. Unit: micromolar (μM).

    Measured: Baseline, Week 2, fellow up

  3. Psychomotor Vigilance Test

    5-minute Psychomotor Vigilance Test measuring sustained attention and psychomotor vigilance. Outcome variables: mean response time, and number of lapses (reaction time >500 ms). Administered via standardized software on a tablet/computer in a quiet environment. Unit: milliseconds (ms).

    Measured: Baseline, Week 2, Week 3, Week 4, Follow-up (Week 1-2 post-altitude)

  4. Maximal Oxygen Uptake (VO2max)

    Maximal oxygen uptake measured during a graded exercise test on a rowing ergometer using a portable metabolic cart. Protocol: incremental ramp test (starting at 100W, increasing 20W every 2 minutes) until volitional exhaustion. Unit: mL/kg/min.

    Measured: Baseline (Week 0), Follow-up (Week 5-6 post-altitude)

  5. White Blood Cell Count (WBC)

    Total white blood cell count measured from fasting venous blood sample using automated hematology analyzer. Unit: 10^9 cells per liter (10^9/L).

    Measured: Baseline, Week 2, Follow up (Week 5-6 post-altitude)

  6. Neutrophil Count (NEUT)

    Absolute neutrophil count measured from fasting venous blood sample using automated hematology analyzer. Unit: 10^9/L. Baseline, Week 4 11 Platelet Count (PLT) Platelet count measured from fasting venous blood sample using automated hematology analyzer. Unit: 10^9/L.

    Measured: Baseline, Week 2, Follow-up (Week 5-6 post-altitude)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted29 May 2026
  2. Study start25 May 2026 (estimated)
  3. Primary completion25 Jun 2026 (estimated)
  4. Study completion25 Jun 2026 (estimated)

Resources

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 (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07615478
Sponsor's protocol ID
202502AS100005-2
Acronym
HSCF-AHT
Status last verified
May 2026
First submitted
19 May 2026
Last updated
29 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided: The project is still ongoing, and there are no current plans to contribute the data. Whether to share it will be considered after the data is officially published.

Publications

  • Roerink ME, van der Schaaf ME, Dinarello CA, Knoop H, van der Meer JW. Interleukin-1 as a mediator of fatigue in disease: a narrative review. J Neuroinflammation. 2017 Jan 21;14(1):16. doi: 10.1186/s12974-017-0796-7.

    PubMed 28109186

  • Goodall S, Gonzalez-Alonso J, Ali L, Ross EZ, Romer LM. Supraspinal fatigue after normoxic and hypoxic exercise in humans. J Physiol. 2012 Jun 1;590(11):2767-82. doi: 10.1113/jphysiol.2012.228890. Epub 2012 Apr 2.

    PubMed 22473785

  • Ando S, Tsukamoto H, Stacey BS, Washio T, Owens TS, Calverley TA, Fall L, Marley CJ, Iannetelli A, Hashimoto T, Ogoh S, Bailey DM. Acute hypoxia impairs posterior cerebral bioenergetics and memory in man. Exp Physiol. 2023 Dec;108(12):1516-1530. doi: 10.1113/EP091245. Epub 2023 Oct 29.

    PubMed 37898979

  • Koral J, Oranchuk DJ, Wrightson JG, Twomey R, Millet GY. Mechanisms of neuromuscular fatigue and recovery in unilateral versus bilateral maximal voluntary contractions. J Appl Physiol (1985). 2020 Apr 1;128(4):785-794. doi: 10.1152/japplphysiol.00651.2019. Epub 2020 Mar 12.

    PubMed 32163332

  • Amann M, Sidhu SK, McNeil CJ, Gandevia SC. Critical considerations of the contribution of the corticomotoneuronal pathway to central fatigue. J Physiol. 2022 Dec;600(24):5203-5214. doi: 10.1113/JP282564. Epub 2022 Nov 23.

    PubMed 36326193

  • Tamaoki S, Matsumoto S, Sasa N, Hoei T, Tojo R, Nakamura T, Aoyagi Y. Effects of sodium bicarbonate bath on the quality of sleep: An assessor-blinded, randomized, controlled, pilot clinical trial. Complement Ther Clin Pract. 2023 Feb;50:101714. doi: 10.1016/j.ctcp.2022.101714. Epub 2022 Dec 14.

    PubMed 36528983

  • Grgic J, Pedisic Z, Saunders B, Artioli GG, Schoenfeld BJ, McKenna MJ, Bishop DJ, Kreider RB, Stout JR, Kalman DS, Arent SM, VanDusseldorp TA, Lopez HL, Ziegenfuss TN, Burke LM, Antonio J, Campbell BI. International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. J Int Soc Sports Nutr. 2021 Sep 9;18(1):61. doi: 10.1186/s12970-021-00458-w.

    PubMed 34503527

Questions about this trial

What is this clinical trial studying?

A study testing Natural recovery, Hot water immersion and Hot spring balneotherapy in people with Central Fatigue and Altitude Training, 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 6 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: looking for participants now, as of the sponsor's last update on 29 May 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?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Ziyue Ou, PHD (+8615626121623, p2521734@mpu.edu.mo), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Voluntary Activation (time frame: Baseline (Week 0), Week 2, Week 3, Week 4 (post-intervention), Follow-up (Week 1-2 post-altitude)). The study lists 2 primary outcomes in all. 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 NCT07615478, which also lists 7 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 29 May 2026.

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