Go for an easy six-mile run in Southern California's Death Valley and you'll overheat as quickly as an air-cooled Volkswagen chugging over Teton Pass in August. Extreme heat compromises your body's ability to cool itself, even to a lethal extent. But that doesn't dissuade approximately 90 racers from competing in the Badwater Ultramarathon, a 135-mile footrace held each July from the depths of Death Valley to the finish line at 8,360 feet on the flanks of Mount Whitney. That's partly because heat, like altitude, can be beaten back with acclimatization. And eight to 14 days usually does the trick. For one to two weeks prior to your trip, train in temperatures similar to those of your destination; your heart rate, core temperature, psychological perception of exertion, and susceptibility to fainting will all decrease significantly.
| Burning ambition: Lisa Smith keeps her cool in the Badwater Ultramarathon.|
Easier said than done? Perhaps, but at least a few athletes have come up with some inventive solutions to training in the heat. "Beginning six to eight weeks prior to an event," says Marshal Ulrich, four-time Badwater champion, "I go into a sauna three to four times a week, crank the heat, and run in place for an hour and a half." Extreme conditions expert Lawrence Armstrong, however, cautions against such radical workouts. "That can be quite dangerous since the heat can't dissipate into the atmosphere, and it doesn't simulate the right conditions because saunas are generally much hotter." Armstrong offers a more reasonable, though only slightly less uncomfortable, acclimatization strategy: Wear extra clothes during training and monitor your core temperature before and after your workout with a rectal thermometer (sorry, it's the best way to get an accurate core temp reading). You'll want to reach a postworkout range of 101 to 102 degrees Fahrenheit.
Muscle cramps, caused by sodium deficiency, are another hot-weather hurdle. "I'll normally take salt pills every two hours and I add a teaspoon of salt to every water bottle I use," says Lisa Smith, the women's champ in the 1999 Marathon des Sables in Morocco. "The entire time I'm out there, I'm thinking prevention. Once you need salt, it's already too late." —CHRIS KEYES
Dress for success:White, moisture-wicking garments will help reflect the heat, and covering your entire body, including head, legs and arms will keep your skin from broiling in the sunshine.
Measure your sweat: Weigh yourself (naked) before and after one hour of exercise in the heat and note the difference. During activity, drink one pint of fluid every hour for every pound of weight lost.
Choose your fluid: During intense workouts (70 percent of your VO2 max, the amount of oxygen your muscles burn during maximum exertion) longer than one hour, sports beverages are more beneficial than water because they replace carbohydrates and electrolytes.
Short-term adaptations to the cold don't really exist," says Murray Hamlet, a cold-injuries expert at the Army Research Institute for Environmental Medicine in Natick, Massachusetts. "Long-distance ocean swimmers can put on more subcutaneous fat and end up looking like porpoises, but that's not a regimen I would recommend to a runner or a cyclist."
| Freeze frame: John Stamstad hammers the last 30 miles in last March's Iditasport.|
Performing in ice-box events like Alaska's Iditasport, a 100-mile human-powered (i.e., choose your instrument of pain: bike, feet, skis, or snowshoes) race near Fairbanks each February, hinges largely on your body's ability to counteract rapid heat loss. Repeated exposure to cold air prior to the event can help build resistance to skin cooling and lower your shivering threshold, but such acclimatizing must take place over long periods of time. "Graded exposure," a process in which you subject yourself to cold for short periods over a few days, can help athletes mentally prepare for such an environment, but beyond that, the best way to conduct yourself while nordic skiing, snowshoeing, ormountain-biking in the cold is through careful temperature management and diligent hydration. "A lot of people don't realize how dry the cold air is," says veteran Iditasport racer Chris Kostman, "but when you exhale, and you can see your breath, what you're really seeing is water leaving your body."
Temperature management may not be as simple as it sounds. Aerobic activity will raise your core temperature, encouraging heat loss through sweating; get too cold, and chilled nerve endings instruct the body to retain heat. The ill-prepared often overcompensate for these variations with too much clothing or through overexertion. For rigorous events in extreme cold, you may need to dress lighter than you think in order to stay pegged in the comfort zone. "What's surprising is how little clothing I wear up in Alaska," Kostman says. "Most of the time, I'll only have two layers on." —C.K.
Warm up slowly: In the cold, engage in 30 minutes of aerobic activity at 50 percent of your VO2 max before your event.
Adopt a liquid diet: If you're going to be on the trail for more than a few hours, quaff drinks like Enduro Booster. They take less energy to metabolize and simultaneously rehydrate you.
Plan your route: Before you embark on a subzero run or bike, keep wind direction in mind. Travel with the wind to warm up and against it once you're warm.