Hot water bath can not only remove dirt from skin, keep sweat glands unobstructed, improve skin's metabolic function and disease resistance, but also make clean skin surface acidic and inhibit the growth of bacteria. In addition, hot water bath can also promote metabolism and eliminate fatigue. Frequent hot baths can improve the excitability of nervous system, promote blood circulation and improve the nutritional status of tissues and organs. At the same time, it can also reduce muscle tension, relieve muscle spasm, relax muscles and eliminate fatigue.