Reason:
Due to strenuous exercise, the body consumes a lot, and the functions of all parts are at a low level. At this time, if you drink a lot of water, it will inevitably lead to excessive burden on your heart, and drinking a lot of raw water and cold water will also stimulate your stomach and cause "stomach pain", which is not good for your health.
The correct way:
Drink a small amount of water after strenuous exercise, and then increase the amount of water after a period of rest. Never drink raw water or cold water.