Jun 25 2009
Exercising in hot weather
For many people, the onset of summer and hot weather leads to a rush outdoors for activity and exercise. Get active, by all means, but be aware of the dangers that come with hot weather exercise. You should begin taking hot weather precautions when the temperature rises above 80° Fahrenheit. High humidity (above 75 percent to 80 percent) can contribute to overheating, so be especially careful when it is hot and humid. Precautions are especially important for the very young and the very old, as well as for anyone with high blood pressure, coronary artery disease or any other kind of cardiovascular disorder.
Dehydration and Overheating
The most general dangers from heat are dehydration and overheating. Water lost through perspiring comes directly out of your bloodstream. If the water isn’t replaced, you can develop heat exhaustion, a condition marked by fatigue, dizziness, pale skin and shortness of breath. Heat exhaustion can occur in as little as 30 minutes if you’re sweating heavily.
The solution: Stay well hydrated at all times. Drink at least a pint of water before your workout, and continue taking water during and after the exercise session. Drink even if you’re not feeling thirsty. Your thirst mechanism is not always a reliable indicator of how much water you’ve lost.
Helpful Tips
- To tell whether you’re dehydrated, check the color of your urine. It should be pale yellow. If it’s darker, you need to drink at least a pint of water.
- Work out in the early morning or late evening when temperatures have dropped.
- Don’t judge your hydration level by how much you appear to be perspiring. In a dry climate, you’ll actually sweat up to 10 percent more than in a humid climate, even though you seem to be sweating less. (Reason: the sweat evaporates much faster in dry weather.)
- In hot weather, wear light-colored, porous clothing that allows sweat to evaporate freely. Full evaporation requires wet clothing, so avoid changing into a dry shirt.
- Drink as often as possible. When exercising or competing for more than an hour, use sports drinks in addition to water. If you prefer a fruit juice instead, dilute it with water and a pinch of salt.
- If you move from a cool environment to a hotter one, allow your body several weeks to adapt.
- If the temperature and humidity are too high, move the workout inside.
Source: Aetna InteliHealth
