8 glass of water every day To prevent heat stroke and other heat-related illnesses, it's essential to stay hydrated. The amount of water needed varies depending on factors such as temperature, humidity, activity level, and individual differences. As a general guideline, aim to drink at least 8 glasses of water per day, and more if you're engaging in physical activity or are in a hot environment. It's also crucial to listen to your body's signals of thirst and drink water regularly throughout the day to stay hydrated. If you're sweating heavily or exposed to high temperatures, you may need to increase your fluid intake to replace lost fluids.