Alternating hot and cold water for bathing has certain benefits. The alternation of the two will increase the elasticity of the blood vessels and improve the internal environment of the blood vessels, which is very beneficial for improving the blood circulation and nutritional status of the human body. It can regulate the internal environment of the human body, including making some inflammatory factors as soon as possible to subside, etc. For men, the alternating hot and cold water stimulation can significantly improve sexual function, because the human body appears sexual function, to a large extent, depends on the contraction of blood vessels. Through the exercise of blood vessels, it can improve male impotence, premature ejaculation, seminal emission, slippery semen and other sexual dysfunction.