Intense training—as in a marathon or preseason training camps during hot summer months—requires extra care. For a routine workout lasting less than an hour, you may not need to consume much extra fluid, electrolytes, or carbohydrates during the activity. But for longer events or an extended, strenuous workout, it’s possible to become dehydrated or experience a number of other problems. Fortunately, specially formulated beverages can help keep you hydrated and prevent common problems associated with extended exercise.
When liver and muscle stores of glycogen (stored glucose, or the body’s fuel) are depleted, your pace in any demanding physical activity slows. It’s important to restore glycogen by consuming carbohydrates, which are needed for maintaining balanced blood sugar. As blood sugar levels drop, fatigue sets in. Low blood sugar is not life threatening (unlike dehydration) for most people, but it does impair performance. Carbohydrate loading in the days prior to a big event will help store extra glycogen, but for long-duration events like a marathon or triathlon, you may need to consume an immediate form of calories two to four hours before exercise.
While not as common as dehydration, hyponatremia (or salt depletion) can be a serious problem in long-duration events—especially in high heat. An athlete may lose more than a liter of sweat per hour, which can deplete important minerals. Supplementing with electrolytes may help maintain the body’s balance and replenish mineral stores during vigorous or prolonged sweating.
The Right Solution
Many individuals attempt to offset water, blood sugar, and mineral depletion through the use of a sports drink. The rate at which a sports drink is absorbed is dependent on osmolality (the concentration of particles in a given amount of fluid). Drinks with an osmolality greater than the body’s natural balance delay nutrient absorption.
According to Daniel Fabricant, PhD, CSCS, vice president of scientific and regulatory affairs at the Natural Products Association, “When selecting a sports drink, check the label. Add the grams of protein and carbohydrates per serving, and then divide by mL of fluid per serving. If that number falls between 5 to 10 percent, most likely the osmolality will be very similar to the blood and thus the fluid, nutrients, and other beneficial ingredients like electrolytes/minerals will be rapidly absorbed.”
An Effective Drink
Research shows that a sports drink with a 5 percent carbohydrate solution containing potassium, sodium, calcium, magnesium, and other electrolytes significantly prolongs exercise duration in long-distance runners. A recent study of teenage tennis players shows that a 6 percent carbohydrate/electrolyte drink was more effective than water in minimizing fluid loss and core temperature responses during training in hot weather.
Other Beneficial Ingredients
Some drinks provide antioxidants such as beta carotene, quercetin, and vitamin C, which can help protect athletes against oxidative damage from high activity levels. Last year, researchers compared a sports drink (6 percent carbohydrate) plus protein, one without protein, and water in 13 slightly dehydrated individuals. During a three-hour recovery period, the sports drink with added protein improved fluid retention 15 percent better than the sports drink alone and a whopping 40 percent better than water.