Effect of Hot Spring Therapy on Autonomic Nervous System and Exercise Performance During Altitude Training

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.

Inclusion Criteria:

• 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

Exclusion Criteria:

• 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