Whether you are an avid runner, a weekend warrior, or someone who spends hot summer afternoons doing yard work, knowing what your body needs can help you decide what to drink before, during, and after vigorous activity.
As many Americans strive for fitness, the industry for sports drinks continues to grow, making selections sometimes confusing.
“Making sure you adequately rehydrate following activity is the biggest area of importance, but preparing your body before and during exercise also is needed,” says David N.M. Caborn, M.D., orthopedic surgeon and head of the sports medicine section at the University of Kentucky Chandler Medical Center.
“If you are outside an hour and a half continuously exercising, either cutting grass, playing softball, or participating in other activities, there is a significant reduction in glycogen-a complex sugar that is an energy source for muscles.”
To prevent dehydration or reduction in glycogen levels, the body must be properly prepared before activity begins, Caborn says. Before exercise, it is best to consume about 16 ounces of water or a sports drink containing a high content (20 to 40 percent) of carbohydrates.
During activity about 8 ounces of liquid every 20 minutes is needed, Caborn says. That can be absorbed easily by the body, such as water or sports drinks with a very low carbohydrate content, should be consumed. In warm weather, a drink with about 3 to 6 percent carbohydrate content is best, and in cold weather a drink that contains 6 to 10 percent carbohydrates should be consumed, Caborn says.
“These low levels of carbohydrates will improve your activity level if you work out for two to two and a half hours,” Caborn says. “However, if you’re active for less than two hours, it won’t make much difference whether you consume a sports drink or just
Following activity, the goal is to restore liquids to prevent or help dehydration. But even without vigorous activity, a day outdoors in the summer can cause dehydration, so the body needs plenty of fluids, Caborn says.
“The optimal time frame for restoring glycogen and rehydrating is the first 30 minutes after activity,” he says. “After vigorous exercise or a prolonged time in the sun, it is important to rehydrate by drinking fluids with a high carbohydrate content-as much as you can tolerate-to restore glycogen.”
Overall, most of the sports drinks on the market today are pretty good in quality, Caborn says. “The main types of drinks to avoid are those with fructose or those with a lot of sugar,” he says. “But to get optimal results and performance during a workout or activity, nothing supplements the need for well-balanced meals and good nutrition.”
What to drink with exercise
Before: 16 ounces of liquid, high carbohydrate level
During: 8 ounces every 20 minutes, low carbohydrate level
After: Drink as much as you can tolerate within 30 minutes, high carbohydrate level