When and Why to Hydrate

DON'T SWEAT YOUR LIFE AWAY
Know when to hydrate and why.
From Help, May 2002
by Selene Yeager
 

Hydration is the Holy Grail of sports nutrition. We hear the mantra: "Hydrate or die!" and heed the grave warnings of experts to slosh down bottles' and bladders' worth while we're on the bike. But does all this imbibing really boost performance? And if so, how do those wicked-fast, überfit 'cross guys race-and kick ass-without carrying a drop of liquid or even taking a hand up in the feed zone? The answer: How much water you really need varies from rider to rider and from day to day. Here's the real deal on how to stay hydrated.

Are you a hammer or a horse? The pros can tear it up without chugging it down for two reasons: They're lean and they're fit. "Lean riders with high VO2 maxes (that's the measurement, in millimeters, of the maximum amount of oxygen that you can take in and process during exercise) can dissipate heat more efficiently without sweating," says sports nutritionist and cyclist Ellen Coleman, RD, MPH, of Riverside, CA. "Since they don't lose much fluid in sweat, they don't need to replace much with water." Sinewy hammers (like most pros) have almost zero fat under their skin, so the heat from their working muscles rises easily to the skin and radiates into the air. Stockier riders don't have that advantage, so they need to sweat more to cool off. Also, the less fit you are, the less efficiently you cool, and the more water you need. "Fit riders are usually smart about going into a race well-hydrated," says Coleman, author of Eating for Endurance, "so they don't need to worry about what little fluid they lose in a short race."

Check the mercury. In cool or cold weather-think cyclocross-your body can get rid of excess heat a number of ways (like radiation from your skin, or through your breathing). But when the heat cranks up, especially if it's humid, you need to rely more on sweat. That means even the lankiest hammerhead needs more fluids.

When's the bell lap? In a race that's less than an hour long, you can probably get by without water, provided it's not 98 degrees outside. "Regular Joe racers would probably still benefit from some fluid, however," says Coleman. Anything over 60 minutes, definitely put a bottle in that cage. "Once you lose more than 1% of your body weight in sweat-and that's bound to happen in a race longer than an hour-performance falls fast," says Coleman. "Studies show that for every liter of water you lose, your heart rate goes up eight beats per minute, and your cardiac output-your VO2-drops." That means your normal race intensity feels a hell of a lot harder, you slow down, and you fall off the back.

The How Much and How Often of Hydration

1. Slam a pounder. Whether it's a 25-minute XC short track or an all-day enduro, go into your event hyperhydrated. Drink 16 ounces of fluid-a Bud pounder doesn't count-an hour before your race.

2. Replace what you lose. Hydration means replacing the fluids you lose. During training, practice weighing yourself before and after hard rides. If you lose more than 1% body weight, drink more. Eventually, you'll get a sense of your hydration needs. As a general rule, riders should drink 6 to 12 ounces every 15 to 20 minutes.

3. Gravity riders need bottles, too. "A lot of times, downhillers forget to drink," says DH vet, Marla Streb (LUNA Chix). "But we're out there practicing longer than the cross-country riders are-like eight hours a day-and we have all those pads on. You need to stay hydrated," she says. "Take a bottle with you on the lift and drink a replacement drink, like Revenge, when you're done to wash out some of the lactic acid you've built up so you're not sore the next day."

4. Make it a daily affair. Hydration should be a constant habit. But forget the hooey about needing eight glasses of water every day. You need 64 ounces (eight glasses) of fluid-big difference. Soda, tea, soup, fruit juice, fruit, even a cup of coffee all contain fluid, and they count. "The only thing that doesn't is booze," says Coleman.

For more information on nutrition, go to www.mountainbike.com