EFFECT OF COLD, TEPID AND HOT SHOWER ON AUTONOMIC VARIABLES IN HEALTHY INDIVIDUALS: A THREE-ARMED RANDOMIZED TRIAL

This randomized controlled trial aims to assess and compare the acute effects of cold (15 - 20°C), tepid (26.6 - 33.3°C), and hot (36 - 40°C) showers on autonomic parameters - heart rate variability (HRV), blood pressure, respiratory rate, and galvanic skin response (GSR), in healthy individuals aged 18 - 25 years. Ninety-three participants will be randomized into three intervention arms (n=31 each) , each receiving a 10-minute shower intervention. There is a significant gap in scientific literature concerning the direct effects of different shower temperatures on autonomic function, despite the widespread use of hydrotherapy in both traditional and naturopathic medicine. Existing studies have primarily focused on immersion-based hydrotherapy or isolated effects of cold or hot exposure, with limited research on shower bathing, which is more practical and widely practiced in daily life. This study integrates modern autonomic measurements and offers a comparative model across three temperature ranges, providing objective evidence on how different water temperatures modulate physiological stress responses. The findings may help refine temperature-specific hydrotherapy protocols for promoting autonomic balance, stress reduction, and cardiovascular well-being in clinical naturopathic settings.