During a workout, your body loses water through sweat and respiration, which can lead to dehydration if you don't replenish it. Dehydration can cause fatigue, dizziness, and cramps, and can even be dangerous in severe cases. That's why it's important to drink water before, during, and after your workout. How much water you need to drink during a workout depends on several factors, including the intensity and duration of your exercise, your body weight, and the temperature and humidity of your environment. As a general guideline, aim to drink about 17-20 ounces of water 2-3 hours before your workout, and then another 7-10 ounces every 10-20 minutes during your workout. If you're doing a particularly intense or long workout, you may need to drink more water to stay properly hydrated. You can also consider drinking a sports drink that contains electrolytes, which can help replace the sodium, potassium, and other minerals lost through sweat.