Although you will feel thirsty after exercise, it is not suitable for hydrating. You should replenish water before exercise to prevent your body from overdrawing. The amount of water you drink varies from person to person. To avoid discomfort, it is best to drink water 10 20 minutes before exercise and replenish it immediately after exercise. However, it is not advisable to drink a lot of water at once, about 800cc or less, to avoid gastric malabsorption. Drinking water during exercise should be done in real time before thirst. Don't wait for thirst, high blood concentration, electrolyte imbalance or discomfort, it will be too late, especially when you sweat a lot, you should supplement it in real time.