Usually a person’s daily intake of water is 2500-3000ml, including water from drinking water, vegetables and fruits, drinks and water from eating and drinking soup. This may be increased or decreased depending on the specific situation. If the elderly have water and sodium retention, and the water is not sufficiently transported and metabolized, the daily water intake should be reduced as appropriate, usually by 500-1000ml under the standard water intake, otherwise it will increase the burden of the body and metabolism. In patients with hypometabolic diseases, such as thyroid insufficiency or adrenocortical insufficiency, the amount of water intake should be reduced as appropriate, usually by 500 ml. In patients with chronic heart failure and chronic renal failure, the daily intake of water should be reduced by 500-1000 ml or more depending on the condition. For patients with endocrine hyperactivity, such as hyperthyroidism or heat stroke in summer, a large amount of rehydration is required, and the daily intake of water should be increased by 1000-1500ml on top of the original basic amount.