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Japanese steam sand bath heat therapy mediates comparable reductions in blood pressure with smaller discomfort and respiratory strains than hot water immersion and sauna
Within-subject crossover trial in 14 healthy young men comparing 20-minute steam sand bath (~50°C), hot water bath (~41°C), and dry sauna (~80°C): mean and diastolic arterial pressures fell similarly after recovery across modalities, while steam sand produced greater thermal comfort and smaller drops in end-tidal CO2 versus water immersion and sauna.
Design
- n = 14 healthy young men
- Crossover: three 20 min sessions—(1) steam sand bath ~50 °C, (2) hot water ~41 °C, (3) sauna ~80 °C (counter-balanced)
- Measures: core temperature, PETCO₂, arterial BP, comfort ratings
BP / strain (abstract)
- Mean arterial pressure & DBP declined by end of recovery for all modalities (p < 0.001 each) with no significant between-modality difference (p > 0.39)
- Core temperature rise: hot water > sauna > steam sand (p < 0.001)
- PETCO₂: stable in steam sand vs falls in hot water and sauna (p < 0.001)
- Thermal comfort (end heating): better (more comfortable) in steam sand vs both other conditions (p < 0.001)
Evidence hygiene
Acute physiology in small healthy male sample—do not extrapolate to CVD patients without medical clearance; complements heat-therapy dose–comfort discussions more than chronic outcome claims.
Publication
Horiuchi M, Chen M, Ishii K, et al. Eur J Appl Physiol. 2026 Mar;126(3):675–688. PMID 40879771.
Outcomes
- Diastolic Blood PressuremmHg (Millimetres of Mercury)
- Steam sand bath produced greater thermal comfort and smaller respiratory (end-tidal CO2) strain than hot water immersion or sauna despite lower core temperature rise.