To keep your body healthy and working properly, you need to make sure to drink enough liquids. It’s especially important to drink enough when you’re exercising or when it’s hot out.
Water makes up at least 55% of your body—maybe as much as 70%, depending on your physique. Three-quarters of your muscle tissue and one-fourth of your fatty tissue is composed of water, according to the American Council on Exercise (ACE).
But your water content isn’t a constant: You lose water with a number of different activities every day, especially when exercising and during warmer weather.
To stay hydrated, you need to be sure that you take in as much water as you lose.
Why water is important
Since your body is mostly water, you obviously can’t live without it.
It protects your organs and helps your digestion. Your body’s cells need water to transport nutrients and get rid of waste.
Perhaps most important, water regulates your body temperature through sweat. When you get hot, sweating cools you down.
According to the ACE, you can sweat away as much as a quart of body water in one hour of physical activity.
That’s good news and bad news: The good news is that sweating during exercise probably means you’re getting a good workout. The bad news is that you’ll become dehydrated if you aren’t replacing the water that you’re losing.
Stay hydrated, stay healthy
Most people can let thirst be their guide to staying hydrated, according to the Institute of Medicine (IOM).
But thirst is a sign that you’re already on the way to dehydration, according to the ACE. To stay healthy, you may need to do more than just quench your thirst.
Drink extra when you exercise. The ACE offers these guidelines:
- Drink 17 to 20 ounces of water two to three hours before exercise.
- Drink 7 to 10 ounces of fluid every 10 to 20 minutes during exercise.
- Weigh yourself before and after workouts. Drink 16 to 24 ounces of fluid for every pound you lost during exercise.
Other tips to stay hydrated include:
- Drink small amounts often instead of large amounts rarely
- Drink cold beverages to cool your body down
- Watch for small amounts of urine or dark-colored urine, which can be a sign you aren’t drinking enough water
A note for long-distance runners
People who participate in marathons, triathlons or race walking should be aware of the risk for hyponatremia, a low level of sodium in the blood which can occur as a result of drinking too much water. To stay hydrated and reduce the risk of hyponatremia, runners should drink enough to replace the fluids lost during exercise and should let thirst be their guide, according to the ACE and USA Track & Field, the governing body of track and field.
For more information on how much water to drink during your exercise routine, talk to a health care professional.