Beat the Heat
Hot summer temperatures getting you down? Cool Running explains the art of cool running and the need to respect sun and heat.
Posted Sunday, 8 July, 2001
There's nothing like the call of a bright, warm day to draw a runner out to the roads for an energizing run. But when that bright warmth becomes just plain heat, your pleasant summertime jaunt can turn into a difficult slog if you're unprepared.
Take the heat seriously. Beyond being merely uncomfortable, it can be dangerous under extreme conditions. If you do not take proper precautions or if you push beyond your limits, your blood pressure can drop too low or you could suffer heat exhaustion. No matter how fit you are, no matter how strong a runner, the heat of summer should not be underestimated. If your body's natural cooling system cannot keep up, you will shut down.
Give yourself a chance to get used to running in the heat. As temperatures rise in the summer, scale back your effort and gradually build back. It takes about two weeks to acclimate to hot temperatures. Understand, though, that you probably cannot and should not run as fast as you did in cooler weather. Adjust your pace and your goals, and take walk breaks if necessary. Run shorter distances if necessary.
Precautions Against the Heat>
On very hot days, absolutely avoid running at midday. Early morning and late evening runs can make for cooler jaunts, and in the case of morning outings, you'll also have less air pollution in urban areas. Try to begin your run with the wind at your back so that you will have a cool headwind on your return. Avoid direct sun by running in the shade as much as possible; don't forget to wear sunblock for runs over 20 minutes.
Dress lightly, and wear light-colored clothes. Avoid cotton t-shirts, which will become soaked and heavy and prevent evaporation of your sweat, which is how your body cools itself. Not incidentally, wet t-shirts also mean chafing and in men can result in bloody nipples. Instead, wear singlets in lightweight, breathable fabrics like Coolmax. See our overview of running fabrics ("The Well-Dressed Runner") for details on this and other space-age fabrics.
Before you head out, drink a big glass of water and then bring a water bottle along for the run. Water is your best protection against heat exhaustion, and you should have about a cup of water every 15 or 20 minutes during your run. It doesn't hurt to pour some over your head once in a while, either. Whatever you do, do not wait until you are thirsty to drink. By then it will be too late, and you could be well on your way to heat exhaustion.
The first sign of trouble is often heat cramps in your legs. Stop and massage them, and try drinking some salt water. However, if you start feeling dizzy and dehydrated and your pulse and breathing grow very rapid, you probably have heat exhaustion. This is brought on partly by fluid loss (sweating) and partly because your body has sent so much blood to the skin to help cool you down. Your brain actually stops getting enough blood and oxygen. Stop exercising immediately. Get out of the sun, get some rest and drink loads of fluids (preferably at room temperature, perhaps with a pinch of salt in every glass). Try taking a cool bath.
If you ignore the signs of heat exhaustion, you risk running into full-fledged heat stroke. This is not to be taken lightly and can even be fatal. The condition is marked by chills, difficulty breathing, confusion, nausea, dizziness, diarrhea, and a lack of sweating, even though the runner is very hot. Immediate medical attention is called for.
Just use common sense. Take it easy, and enjoy your run. If you begin to feel dizzy or sick on a run, stop running and get out of the sun.