Working up a good sweat when you exercise lets you know you’re working hard, but it’s also a sign that you’re losing water — water that needs to be replaced.
Water not only regulates your body temperature, but it also helps lubricate joints and transport nutrients. If you’re not properly hydrated, you won’t be able to perform at your peak. You could even experience fatigue, cramps and more.
And thirst is a sign that you’re already getting dehydrated.
You want to prep before you take your first workout step. In fact, no matter what time you exercise, it’s essential to hydrate throughout the day.
A good rule of thumb is to drink 2 cups of water in the hours before exercise and then another cup 20 minutes in advance. During exercise, drink up to one cup every 20 minutes or so. When working out for over an hour, you may need a sports drink. After the workout, have a cup of water within half an hour.
Here’s an example of a hydration schedule.
- Up to 2.5 cups of water over 2 to 4 hours pre-workout
- Up to 1 cup of water 20 minutes pre-workout
- 0.5 to 1 cup of water every 20 minutes
- 1 cup of water within 30 minutes
- More as needed: 2.5 to 3 cups of water for each pound lost
You can tell if you’re properly hydrated if your urine is light in color. The darker the color, the more dehydrated you are. For a more exact reading, weigh yourself before and after exercise.
Water weight loss can be dangerous. Just a 1 percent change in your body weight can signal dehydration.
The American Academy of Family Physicians has more on the importance of hydration for exercise, as well as warning signs of dehydration.