Physical and Mental Effects of Bathing: A Randomized Intervention Study
Showering is the most common form of bathing worldwide. Whole-body immersion bathing in warm water (~40°C ~104°F) is common in Japan and exerts sufficient hyperthermic action to induce vasodilatation and increase blood flow, supplying more oxygen and nutrients to the periphery. Cross-sectional studies report better subjective health status with an immersion bathing habit. This randomized controlled trial compared the effects on health of immersion bathing and shower bathing in participants who received 2-week intervention of immersion bathing in warm water (~40°C ~104°F) for 10 min followed by 2-week shower bathing without immersion or vice versa. Visual analog scale scores were significantly better for fatigue, stress, pain, and smile and tended to be better for self-reported heath and skin condition after bathing intervention than after showering intervention. The SF-8 Health Survey showed significantly better general health, mental health, role emotional, and social functioning scores. Profile of Mood State scores were lower for stress, tension-anxiety, anger-hostility, and depression-dejection. Immersion bathing, but not shower bathing, exerts hyperthermic action that induces increased blood flow and metabolic waste elimination, which may afford physical refreshment. Immersion bathing should improve both physical and emotional aspects of quality of life.
Lifestyles can vary widely, and several lifestyle factors such as diet, exercise, sleep, alcohol consumption, and smoking are associated with health and survival. Another aspect of lifestyle that varies is bathing, several forms of which include bathing in a conventional shower, steam shower, sauna, or bathtub. Bathing in a shower is the most common form of bathing. It is known that the most beneficial effect of so-called immersion bathing is vasodilation induced by hyperthermic action, which results in systemic elevation of the supply of oxygen and nutrients to the periphery and increased elimination of carbon dioxide and metabolic waste materials.
A survey of bathing practices in Japan revealed that 80% of participants enjoyed bathing and reported sensations or feelings of warmth, relaxation, relief from fatigue, and refreshment after immersion bathing.
Results of the Study showed that routine immersion bathing appeared more beneficial to mental and physical health than routine shower bathing without immersion. Further interventional studies that consider seasonal factors and physiological factors in relation to effective bathing temperature and timing are anticipated to show the effect of immersion bathing and clarify the beneficial effects on health.
Source:Goto, Yasuaki et al. “Physical and Mental Effects of Bathing: A Randomized Intervention Study.” Evidence-based complementary and alternative medicine : eCAM vol. 2018 9521086. 7 Jun. 2018, doi:10.1155/2018/9521086