Water is very important to human body, it can participate in life movement, eliminate harmful toxins, help metabolism, maintain aerobic respiration and so on. 1, Help digestion: The food we eat in our mouth, after being chewed by our teeth and wetted by saliva, goes through the digestive process from esophagus to stomach, and is digested and absorbed. All these links need water to participate, so as to accelerate the dissolution of nutrients by body fluids. 2. Excretion of waste: The residual waste after the nutrition digestion and absorption of food should be excreted through sweating, breathing and excretion. These different ways of excretion need the help of water. 3, lubrication joints: human joints need lubrication fluid to avoid damaging friction between bones, and water is the main source of joint lubrication fluid. 4. Balance body temperature: When the ambient temperature is lower than the body temperature, in order to maintain the body temperature and ensure normal physiological activities, the water in the body will remain in the body due to the reduced evaporation of the narrowed pores; When the ambient temperature is higher than the body temperature, water will pass through the dilated capillaries.