Effects of Bicarbonate Spring Water Immersion on Cognitive Reliability and Post-Maximal Exercise Recovery in Adolescent Rowers During Altitude Training: A Sex-Stratified Three-Arm Randomized Controlled Trial

July 31, 2026 updated by: Ziyue Ou, Macao Polytechnic University

A Sex-Stratified Block-Randomized Controlled Trial of Bicarbonate-Rich Thermal Water Immersion on Cognitive Reliability and Post-Maximal Exercise Recovery in Adolescent Rowers During Field-Based Moderate-Altitude Training

This randomized controlled trial aims to investigate the effects of hot spring bath therapy on cognitive function recovery, cerebral hemodynamics, and athletic performance in athletes undergoing altitude training. Participants will be randomly assigned to either a hot spring intervention group, a hot water control group, or a blank control group. The hot spring intervention group receives hot spring baths (38°C, 20 minutes) combined with altitude training; the hot water control group receives hot water baths (38°C, 20 minutes) combined with altitude training; and the blank control group receives standard recovery procedures combined with altitude training. Primary outcome measures include cognitive performance assessments (Stroop test, psychomotor vigilance test) and cerebral hemodynamic indicators (functional near-infrared spectroscopy, transcranial Doppler ultrasound). Secondary outcomes included exercise capacity (maximal oxygen uptake, triathlon performance, 500-meter test), blood lactate, and hematological parameters (white blood cells, neutrophils, platelets). These findings may provide evidence for non-pharmacological interventions to enhance cognitive recovery and brain adaptation during altitude training.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

27

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Yunnan
      • Tengyue, Yunnan, China
        • Field altitude-training camp, approximately 1600 m

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Male or female aged 11-17 years- 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
  • No color blindness or uncorrected visual impairment that would affect Stroop test performance

Exclusion Criteria:

  • History of cardiovascular, respiratory, renal, or endocrine disorders
  • Current use of medications affecting autonomic function or cognition (e.g., beta-blockers, anticholinergics, stimulants, sedatives)
  • History of syncope, heat intolerance, or neurological disorders
  • 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
  • History of traumatic brain injury, stroke, or psychiatric disorders

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Natural Recovery Group
Control group participants will undergo the same altitude training protocol (altitude 1600 meters) for 4 weeks. Participants underwent a 20-minute quiet seated rest at 16:00 on Tuesdays, Thursdays, and Saturdays, with ad libitum water consumption permitted and electronic devices prohibited.
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.
Other Names:
  • NR
Active Comparator: 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±0.5°C) in a standardized indoor hot spring facility. The immersion protocol includes partial-body immersion up to the xiphoid process (lower 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 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.
Other Names:
  • HWI
Experimental: 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 ± 0.5°C) in a standardized indoor hot spring facility. The immersion protocol includes partial-body immersion up to the xiphoid process (lower chest) for 20 minutes, performed three times per week, followed by a 10-minute rest before leaving the facility.
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 includes whole-body immersion to the neck for 20 minutes, followed by a 10-minute rest before leaving the facility. Three times per week.
Other Names:
  • HSI

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Psychomotor Vigilance Test (PVT)
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.
5-minute PVT measuring sustained attention and psychomotor vigilance. Outcome variables: mean reciprocal response time (1/RT). Administered via standardized software on a tablet/computer. Unit: second.
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.
Stroop Test Performance
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.
Computerized Stroop Color-Word Test measuring executive function and cognitive inhibition. Outcome variables: reaction time (ms). Administered in a quiet, temperature-controlled room (22-24°C). Unit: milliseconds (ms).
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.
Cerebral Oxygenation (fNIRS)
Time Frame: Baseline, Week 2, Week 5
Changes in oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (HbR) in the prefrontal cortex during cognitive tasks, measured by functional near-infrared spectroscopy (fNIRS) with a multichannel system. Outcome: relative changes in HbO and HbR concentrations. Unit: micromolar (μM).
Baseline, Week 2, Week 5
Cerebral Blood Flow Velocity (TCD)
Time Frame: Baseline, Week 2, Week 4
Mean blood flow velocity in the middle cerebral artery (MCA) and anterior cerebral artery (ACA) measured by transcranial Doppler ultrasound (TCD) with 2MHz probe. Measurements taken in supine position after 10 minutes of rest. Outcome: mean velocity (cm/s). Unit: centimeters/second (cm/s).
Baseline, Week 2, Week 4

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximal Oxygen Uptake (VO2max)
Time Frame: Baseline, Week 5
Maximal oxygen uptake measured using a portable metabolic analyzer during a graded exercise test on a rowing ergometer. Test protocol: incremental ramp test to exhaustion. Unit: mL/kg/min.
Baseline, Week 5
1000-Meter Running Test
Time Frame: Baseline, Week 3, Week4
1000-meter maximal effort running test on a standard 400m track or treadmill. Total completion time recorded. Unit: seconds (s).
Baseline, Week 3, Week4
Peripheral Oxygen Saturation (SpO2)
Time Frame: one month.
Resting peripheral oxygen saturation measured via fingertip pulse oximeter after 10 minutes of seated rest. Unit: percentage (%).
one month.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Macao Polytechnic University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 25, 2026

Primary Completion (Actual)

February 26, 2026

Study Completion (Actual)

March 8, 2026

Study Registration Dates

First Submitted

May 14, 2026

First Submitted That Met QC Criteria

May 19, 2026

First Posted (Actual)

May 27, 2026

Study Record Updates

Last Update Posted (Actual)

August 4, 2026

Last Update Submitted That Met QC Criteria

July 31, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 202502AS100005-1

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

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.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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