In general, the amount of water that people drink is 2500-3000ml per day, but the above situation is exceptional for the elderly, who need to consume 2000-2500ml of water per day, because the basal metabolic rate of the elderly is relatively low, and if they consume too much water, dilutional hyponatremia or water-sodium retention will occur. In addition, for patients with primary hypertension or low metabolic rate, such as thyroid insufficiency and hypoadrenocorticism, the daily water intake should usually be limited to 2500ml, otherwise anterior cervical mucinous edema will occur, which will also increase the load on the heart and kidneys. However, for patients who are dehydrated, the daily water intake should be controlled at about 3500-4500ml to be able to avoid the occurrence of dehydration in the body.