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

NCT07608913 | Completed

• 1 other identifier: 202502AS100005-1
• Study Type: interventional
• Target: 27
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Altitude Training Adaptation; Cognitive Function; Cerebral Hemodynamics; Exercise Performance; Hydrotherapy; Balneotherapy; Hypoxia

Keywords

Altitude Sickness; Cognition; Cerebrovascular Circulation; Physical Performance; Hydrotherapy; Hot Springs

Outcome Measures

Primary Outcomes (4)

• Psychomotor Vigilance Test (PVT)

  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

  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)

  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)

  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 Outcomes (3)

• Maximal Oxygen Uptake (VO2max)

  Baseline, Week 5

• 1000-Meter Running Test

  Baseline, Week 3, Week4

• Peripheral Oxygen Saturation (SpO2)

  one month.

Study Arms (3)

Natural Recovery Group

ACTIVE COMPARATOR

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

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±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

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 ± 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

Interventions

Control Group：Natural Recovery BEHAVIORAL

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.

Also known as: NR

Natural Recovery Group

Hot water immersion group BEHAVIORAL

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.

Also known as: HWI

Hot water immersion group

hot spring immersion group BEHAVIORAL

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.

Also known as: HSI

Hot Spring Immersion Group

Eligibility Criteria

• Age: 11 Years - 17 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Macao Polytechnic University: lead

Study Sites (1)

Field altitude-training camp, approximately 1600 m

Tengyue, Yunnan, China

Location

Related Publications (6)

• 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 BACKGROUND

• MacLeod CM. Half a century of research on the Stroop effect: an integrative review. Psychol Bull. 1991 Mar;109(2):163-203. doi: 10.1037/0033-2909.109.2.163. No abstract available.

  PMID: 2034749 BACKGROUND

• Ando S, Hatamoto Y, Sudo M, Kiyonaga A, Tanaka H, Higaki Y. The effects of exercise under hypoxia on cognitive function. PLoS One. 2013 May 10;8(5):e63630. doi: 10.1371/journal.pone.0063630. Print 2013.

  PMID: 23675496 BACKGROUND

• 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 BACKGROUND

• Ohori T, Nozawa T, Ihori H, Shida T, Sobajima M, Matsuki A, Yasumura S, Inoue H. Effect of repeated sauna treatment on exercise tolerance and endothelial function in patients with chronic heart failure. Am J Cardiol. 2012 Jan 1;109(1):100-4. doi: 10.1016/j.amjcard.2011.08.014. Epub 2011 Sep 23.

  PMID: 21944673 BACKGROUND

• 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 BACKGROUND

MeSH Terms

Conditions

Hypoxia; Altitude Sickness

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Respiration Disorders; Respiratory Tract Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: OTHER
• 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: January 25, 2026
• Primary Completion: February 26, 2026
• Study Completion: March 8, 2026
• Last Updated: August 4, 2026

Record last verified: 2026-07

Locations

CN (1)