Up to 60% of the human body is water. When we exercise for even just an hour, we can lose anywhere from 0.5–2 liters of that water (depending on factors such as heat and clothing)1.
Whether you’re an elite athlete or a weekend warrior, drinking water during and after exercise is essential if you want to get the most out of your workout—and feel good while you’re doing it. Even if you’re able to drink water while working out, there is a good chance that you’re still losing more water than you’re taking in. You lose water both through your breath and through sweat. Eventually, this water loss catches up with you, and it needs to be replaced.
Hydration is necessary because water and electrolyte balance are critical for the function of our organs and for maintaining health in general. Exercise can cause both fluid and electrolyte imbalances in our body and post-exercise hydration is the only way to fix it.
How Much Water Do You Need?
So how much water should you drink before, during, and after a workout? Well first, make sure you’re well hydrated to begin with. How much water you lose during exercise depends on a few factors including
- the conditions in which you’re exercising (indoors, outdoors),
- genetics, and
- what shape you’re in.
The amount you sweat isn’t an indication of fitness level. However, as you get in better shape your body becomes used to tolerating higher levels of exercise, and you tend to sweat less.
Drink fluids throughout the day before you exercise and then use the Melton formula as a rule of thumb to figure out how much you should drink during and after2:
- One to two hours before your workout: 15 to 20 ounces of water
- 15 minutes before you start your workout : 8 and 10 ounces of water
- During your workout: 8 ounces every 15 minutes
- After your workout: 8 ounces no more than 30 minutes AFTER
This should be used as a guide of how much water you need before, during, and after exercise. More strenuous exercise in higher temperatures will always require you to drink more fluids.
What type of fluid should you drink?
Many people like to use sports drinks during a workout. That’s generally not necessary unless you’re working out for an extended period of time.
If your exercise lasts more than an hour, then hydrating with a sports drink is usually better than plain water. Sports drinks contain carbohydrates and electrolytes like sodium and potassium so after a long period of exercise, they’ll do a slightly better job of bringing your electrolytes back into balance. However, don’t get hung up on sports drinks. In the long run, water is still the best beverage.
1- Healthline. 13 Easy Ways to Lose Water Weight (Fast and Safely). http://www.healthline.com/nutrition/13-ways-to-lose-water-weight#section1
2- WebMD. Water Tips for Efficient Exercise. Reviewed by Brunilda Nazario, MD on July 07, 2009. http://www.webmd.com/fitness-exercise/features/water-for-exercise-fitness#1