The water intake and discharge in the human body are in a basic balance, and the human body has to excrete about 1500ml of urine every day, in addition to some water evaporated by the skin and sweat, or excreted with the stool, so the human body needs to take in about 1500-2000ml of water every day. It should be noted that if the human body has a disorder to excrete water, it may lead to water retention, for example, patients with renal insufficiency or cardiac insufficiency, at this time, we should strictly record the amount of water excretion and calculate the intake according to the amount of excretion to avoid aggravating the accumulation of this water and affecting the burden of kidney function and cardiac function. And if there is a lot of sweating, increase the intake of water to avoid causing dehydration.