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

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.

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