Hot Weather

After a long, cold winter, nothing''s more glorious than being outside on that first 70-degree day.

Problem is, 70 degrees all too soon becomes 80 or 90 or even (gasp!) 100 degrees. Spring becomes summer and summer becomes an oven. The outdoor workout that left you invigorated in April now has you panting like a dog in July. Your feet burn. Your legs ache from heat cramps. Your vision blurs from the quarts of sweat streaming off your brow and the waves of heat shimmering ahead of you. If this is what being one of the boys of summer is like, you''d just as soon be a fall guy. And you will be if you don''t take steps to minimize the effect of hot weather on your athletic performance.

"Hot weather puts all kinds of stresses on your body that aren''t nearly as problematic in cooler situations," says Al Paolone, Ed.D., professor of exercise physiology in the physical education department at Temple University in Philadelphia. First, when we get hot, we sweat—a lot. Sweating results in large water losses. That''s nothing to take lightly—dehydration kills. So does heatstroke, which happens when heat, fluid loss and physical exertion overwhelm your body''s natural cooling system, causing your temperature to skyrocket. Your body could literally cook itself to death.

In hot weather, as in life, it''s the cooler heads that will prevail. "The more you can do to minimize heat and the harmful effects of the sun, the better off you are. That means deflecting sunlight away from you as well as replacing the fluids your body is getting rid of in an effort to keep you cool," says Anthony D. Mahon, Ph.D., associate professor of exercise physiology in the Human Performance Lab at Ball State University in Muncie, Indiana.

Gearing Up for Warm Weather

When it''s 80-plus degrees and the sun''s out, you''re probably thinking all you need to work out is a T-shirt and shorts. Think again. If you don''t prepare yourself adequately to deal with hot weather, you could be facing sunburn, blisters and muscle cramps at a minimum, and heatstroke and skin cancer at a maximum. So take a moment to equip yourself for a hot time. Here''s all you need.

* A water bottle. You can lose up to two quarts of fluid an hour when you''re training in the heat. If you don''t replace that fluid, you can suffer fatigue, headaches, muscle cramps, nausea, dizziness—just some of the signs of dehydration. As it is, you should be drinking six to eight eight-ounce glasses of water a day, at the very least. In addition, drink at least six ounces of fluid for every 15 minutes you''re exercising in the heat, suggests Dr. Mahon. And we don''t mean fluids that contain caffeine or alcohol—those ingredients will actually cause you to lose more fluid. It is also a good idea to be well-hydrated before you start exercising.

* Light, loose clothing. Light-colored, loose-fitting clothing will help keep you cool. Yeah, you were right—wearing a T-shirt and shorts is just fine for the outdoors. But avoid wearing any black or dark colors—they absorb heat and will make you hotter, says Dr. Mahon.

* A brimmed hat. Light clothing is an important part of your warm-weather wardrobe, but a good hat is the real topper to any hot-weather exercise outfit. Make sure that hat is made of plastic mesh or straw—something with plenty of airholes to vent heat. It should also have a good-size brim to protect your eyes and give you extra coverage from the burning sun, suggests Dr. Mahon.

* Sunglasses. Don''t want an eye burn, do you? If you''re spending any time out in the sunshine, and particularly if you are at a place where light reflects easily off surfaces (like a beach or a baseball diamond), you''ll need sunglasses to protect your eyes from retinal burns caused by ultraviolet (UV) rays. For safety''s sake, buy a brand with UV blocking, which will help keep the sun''s radiation from damaging your eyes, says Merrill Allen, O.D., Ph.D., professor emeritus of optometry at Indiana University in Bloomington.

* A layer of sunscreen. We can''t guarantee that sunscreen will improve your athletic performance in hot weather, but it''s probably the most important item you can wear under the sun. Sunscreen keeps the sun''s ultraviolet radiation from penetrating your skin. Yes, that prevents you from getting a tan, but it can also keep you from getting skin cancer. Make sure it has a sun protection factor (SPF) of at least 15, suggests the American Institute for Cancer Research. And buy a brand that''s waterproof, so you won''t sweat the stuff off too quickly.

* Petroleum jelly. Nothing shortens a workout like the searing pain of a blister tearing open, exposing raw flesh to your burning sweat—talk about salt in an open wound. You can keep blisters at bay with just a little dab of petroleum jelly. Rub some onto your heel, the pad of your foot or wherever you''re prone to blisters, suggests Gary M. Gordon, D.P.M., director of the running and walking program at the Joe Torg Center for Sports Medicine at Hahnemann Hospital in Philadelphia. It feels a little slimy at first, but you''ll get used to it.

How to Take the Heat

Even with proper preparation, you''re bound to face some harsh realities of exercising in hot weather.

"Men who are very careful about exercising in hot weather can still end up in the hospital with heatstroke or a heart attack. They may have been in fairly good shape, but the heat got the better of them," says David Spodick, M.D., professor of medicine at the University of Massachusetts Medical School and director of the cardiac fellowship program at St. Vincent Hospital, both in Worcester. Now, you could avoid this fate by, say, joining an air-conditioned gym or taking up swimming as your full-time exercise. Of course, you may be the type who just has to exercise outside, no matter that tar roads are bubbling or trees are spontaneously bursting into flames. In that case, take heed.

Start slow. When you first begin working out in hot weather, be sure to pace yourself, says Dr. Paolone. Keep your workout to about 15 to 20 minutes. Each day, gradually increase your workout time by about 5 to 10 minutes. This will get your body acclimated to hotter weather and decrease your likelihood of suffering a heat-induced injury.

Stay off the tar. Avoid exercising on tracks or streets with tarred surfaces, says Dr. Mahon. Black tar absorbs incredible amounts of heat. That heat will radiate back up off the tar and only make you hotter. Stick to the sidewalk or seek out dirt tracks.

Seek the shade. Try to find places to exercise where there''s shade or shelter from direct sunlight, suggests Dr. Mahon. Running along a tree-covered track will keep you much cooler than running in direct, glaring sun.

Check the climate. When you''re hot, you''re hot, but different kinds of heat will affect your performance in different ways. Humid heat, which can make running feel like swimming, is especially hard on your heart and lungs. Before you go out for exercise, check the humidity—the closer it is to 100 percent, the more you should think about shortening your run.

Conversely, dry heat, so often associated with the arid Southwest, may seem easier to deal with, but it, too, takes its toll. "The problem with dry heat is that you may not realize just how hot it is until it''s too late," explains Dr. Spodick. With dry heat, our sweat evaporates off us as fast as we can perspire it. Consequently, we don''t notice how much fluid we''re losing; that leaves us wide open for dehydration and heatstroke. Either condition could kill you if left unchecked. So if you decide to exercise in dry heat, be sure to bring along plenty of water. Drink it often—and drink before you feel thirsty.

Pepper yourself with salt—cautiously. If you don''t have heart or kidney disease, crunch on a few pretzels or low-fat potato chips after your workout. According to Dr. Spodick, in healthy individuals, eating salty foods after a dehydrating workout can help you retain fluids and increase blood volume. Don''t overdo it—a handful of chips ought to suffice. Warning: If you have high blood pressure or are on a low-salt diet, talk with your doctor first.

Time your workout. Remember that the hottest time of the day is between 10 a.m. and 3 p.m.—that''s also the time when UV radiation from the sun is at its most cancer-causing intense, warns the American Institute for Cancer Research. Try to time your workouts before or after these hours.

Know when to quit. Many of the more dangerous heat-induced ailments are downright insidious. "By the time you feel thirsty, you''re already pretty dehydrated. And a lot of people never spot the signs of heatstroke until they''re lying in the emergency room," says Dr. Spodick. Don''t be one of the numbers. Dizziness, nausea, headaches, diarrhea, irritability, muscle cramps—these are all signs that the heat is getting to you. Stop what you''re doing, get yourself to some place cool and take a breather.