In summer, you should drink water whether you are indoors or before going out, especially when exercising or doing physical activities. It is best to drink 200-300ml of water within 40 minutes to 1 hour before exercise. When sweating a lot, you can add some salt water appropriately. In addition, you can't drink a lot at once when you are thirsty. You should drink several times and drink a small amount each time, preferably 100ml to 150ml each time, with an interval of half an hour. Since the maximum continuous diuresis rate of the human kidney is 16ml per minute, once the water intake rate exceeds this standard, the excess water will cause the cells to swell, causing dehydration and hyponatremia, which generally leads to dizziness, vomiting, weakness, rapid heartbeat and other symptoms. In severe cases, convulsions, coma and even life-threatening may occur.