Intake: The Latest Hydration Helper
By Dana Sullivan

Staying hydrated during a long workout can lead the human athlete to believe that a couple of water-storing humps might be a superior evolutionary trait. Camel envy aside, a substance called glycerol--a naturally occurring component of fat--could be the next best thing. "Glycerol helps the body retain water and slows dehydration," says Dr. Paul Montner, an exercise physiologist and assistant professor of medicine at the University of New Mexico's School of Medicine in Albuquerque. Now the stuff is showing promise as a supplement to help athletes dodge dehydration.

During an hourlong workout, an athlete can lose as much as four liters of water, says Montner. The problem is that most people can comfortably replace only about a liter of it. But drinking the proper dosage of glycerol dissolved in that liter makes your muscles respond as if you've downed a liter and a half. "Glycerol acts like a sponge, storing the water you need for healthy perspiration and circulation." In one UNM test, Montner found that cyclists who drank a combination of glycerol and water were able to work at 60 percent of their maximum for 94 minutes before becoming exhausted. The same group of cyclists, drinking plain water, lasted just 77 minutes in an identical test a week later.

Many health-food stores and bike shops stock glycerol in gel or powder form; look for Glycerate (call 800-295-4335 for information) and Hydro Fuel (800-438-9435). Montner warns that some athletes experience headaches and stomach discomfort after taking glycerol, but he believes that's simply because they overdo it. For every kilogram (2.2 pounds) of body weight, mix about one gram of glycerol with 21 milliliters of water, and the solution should take you to the next oasis.