Natural Energy
by Suzanne Girard Eberle, M.S., R.D.

The sun is shining, and you're set to run your favorite 5-mile loop or perhaps log some miles in the saddle in anticipation of your first mini-triathlon next month. You've got a visor, sunscreen and sunglasses, as well as money for emergencies. What else could you possibly need?

Unfortunately, athletes of all abilities often overlook the obvious: Getting the most out of any workout requires that you pay attention to an important piece of equipment — your body. It requires two essential ingredients to operate efficiently: fuel and fluid. Thanks to the multitude of energy bars (see chart, next page) and sports drinks available, fitness enthusiasts, as well as serious-minded athletes, will find it easier than ever to hydrate and fuel up while on the move.

Drink Up
Dehydration can stop even the fittest athlete in her tracks. When you exercise, your muscles produce so much additional heat that your internal temperature can rise to deadly levels if you don't eliminate the excess. You do that primarily by sweating. In fact, you can lose as much as 1 to 2 quarts of water an hour in the form of sweat as your body tries to regulate its temperature. Water losses of even 1 percent of your weight (for example, 1 1/2 pounds for a 150-pound athlete) impair your ability to regulate your body temperature and cause your blood volume to drop. This means your heart must work harder in order to supply blood to exercising muscles. Besides being unable to maintain your usual pace, you may get dizzy and weak, or even pass out, as you become progressively more dehydrated.

To prevent this dangerous scenario from taking place, you need to hydrate before, during and after exercise. A good rule of thumb is to drink 1 to 2 cups of liquid before exercise, one-half to 1 cup every 15 or 20 minutes during, and 1 to 2 cups following activity.

Most of the time you can prevent overheating simply by drinking water. If you exercise continuously for more than 60 minutes, however, or if you participate in activities that require short, intense bursts of energy, such as basketball, skiing or tennis, drinking a sports beverage is the way to go. Fluid-replacement drinks provide the body not only with water, but also with carbohydrate (glucose, sucrose, fructose, maltodextrins) in a form readily absorbable by exercising muscles. You'll be able to keep going longer, plus your workouts will seem easier, too. Sports drinks also contain electrolytes such as sodium and potassium, which help the body absorb fluid and stimulate your thirst during exercise so that you'll drink more.

Eating for Energy
Energy bars make convenient, fortified snacks, and they also perform admirably as pre- or postexercise mini-meals. In terms of their nutritional makeup, energy bars vary greatly in their content. Most contain a mix of simple and complex carbohydrates, protein, fat, fiber, vitamins, minerals and herbs. If you can tolerate eating energy bars while exercising (for example, during a daylong hike), choose varieties that get at least 60 percent or more of their calories from carbohydrates. This way, you'll extend your body's limited carbohydrate stores, referred to as muscle glycogen — the preferred source of fuel during exercise.

To aid digestion, drink at least 8 ounces of fluid with the bar. Despite the claims, energy bars aren't magical. Try several brands to determine which you can stomach best before, during (if applicable) and after exercise. Keep in mind that energy bars should supplement a balanced, healthful diet, not make up the bulk of it. Sports nutritionist Ellen Coleman, M.P.H., R.D., of The Sport Clinic in Riverside, Calif., agrees. "Active people can get the same energy boost [as from energy bars] from traditional high-carbohydrate snacks such as graham crackers, fig bars, low-fat granola and breakfast bars, low-fat yogurt, and bananas," she says. Homemade fruit smoothies made with soy milk provide another tasty and nutritious option.

Suzanne Girard Eberle is a freelance health writer living in Portland, Ore.