You will sweat a lot during exercise, especially in the hot and humid environment in the south, which will lead to a lot of water loss and dehydration, which will have a negative impact on sports ability and the human body itself. Therefore, it is important to replenish water. "There are two common misunderstandings in sports hydration: one is not thirsty, and the other is to only supplement pure water." Dr. Cao Jianmin pointed out that most people often take thirst as a signal of water shortage, but research shows that when they feel thirsty during exercise, their bodies are already in a state of mild dehydration, and it is too late to replenish water. We should advocate an effective hydration method-hydration before exercise: 300-500ml should be supplemented 30- 120min before exercise, and low-temperature sports drinks are more effective. Low-temperature sports drinks can help reduce the temperature rise and effectively delay dehydration. Hydration during exercise: a small amount and many times. Generally, the total amount of water supplement per hour should not exceed 800 ml, and it is advisable to supplement about 150-200 ml of sports drinks every 15-20 minutes. Hydration after exercise: The best effect is to take sugary and electrolyte drinks, and the sugar content of the drinks can be 10%. Still drink a small amount and many times, and don't drink too much. Under normal circumstances, if you don't have much exercise and sweat, it is enough to supplement pure water, such as boiled water or light tea. However, after a large amount of exercise or long-term exercise, it should be noted that drinking plenty of boiled water can quench thirst for a while, but it will reduce plasma osmotic pressure, increase urine output and delay the rehydration process of the body. Excessive drinking of boiled water will also dilute gastric juice and affect appetite and digestion after exercise. It is recommended to drink sports drinks containing electrolytes and sugar.