1. Help digestion: The food we eat in our mouth is digested and absorbed through the digestive process from esophagus to gastrointestinal tract after being chewed by teeth and wetted by saliva. All these links need water to participate, which accelerates the dissolution of nutrients by body fluids.

2. Waste excretion: the residual waste after digestion and absorption of food nutrition should be excreted through sweating, breathing and excretion. These different ways of excretion need the help of water.

3. Lubrication of joints: Human joints need lubricating fluid to avoid damaging the friction between bones, and water is the main source of joint lubricating fluid.

4. Balance the 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 be discharged from the body through the expanded capillary breathing hole, which will lower the body temperature. The body ensures its survival function through the dispersion of water.

5. Maintain cells: water can promote cell metabolism and maintain the normal shape of cells; Keep skin moist and elastic.

6. Balance blood: Water can improve the circulation of blood and tissue fluid and help balance the viscosity and pH of blood.