Be sure to keep cool when exercising!

Here in Washington, DC, we’re experiencing a brutal and record breaking heat wave, and I thought it would be a good opportunity to review the dangers of exercising in extreme heat and precautions to take when engaging in exercise during warm weather.

Our bodies have two ways of cooling itself off. Both work by dissipating heat from our warmer bodies into the cooler air. The one we’re most familiar with is sweating. As our body temperature increases, sweat, which consists mostly of water and salt, is produced. When we sweat, our skin becomes moist. As the cooler outside air brushes against our skin, sweat is wicked off of our skin, and our bodies become cooled.

When we exercise, our working muscles produce heat that our bodies need to dissipate. Much of the heat that our muscles produce is transferred to our blood. When our body needs to cool itself off, the blood vessels closest to our skin open up and widen, slowing the flow of blood as it passes against our skin, and allows the body’s heat to dissipate out into the environment through our skin. Our blood cools and as it travels back through the rest of our body, the cooler blood keeps our body cooler. However, when the air temperature is greater than our bodies’ temperature, it becomes harder for the body to cool itself off. Mix in humid conditions, and the ability of sweat to evaporate disappears, resulting in an increased risk of the body overheating.

Exercising in extreme heat conditions, especially if someone is not acclimated to the heat, increases the risk of developing symptoms that include muscle cramping and dehydration as well as heat exhaustion, and most dangerously, heat stroke. If you experience any dizziness, nausea or vomiting, lightheadedness, weakness, or muscle cramping, stop exercise, get out of the heat, into a cooler environment, and drink plenty of fluids. If you do not start to feel better shortly after getting out of the heat and rehydrating, you need to seek emergency treatment ASAP.

There are things that increase the risk of developing heat-related illness. Being older, overweight, dehydrated, not acclimated to heat, having a low fitness level, engaging in high exercise intensity exercise, consuming alcohol, caffeine, and wearing tight-fitting dark clothing.

If you are going to exercise in the heat, be sure to wear lightweight, light colored, loose clothing, that is made of a moisture wicking fabric. Be sure to stay well hydrated and avoid exercising in the middle of the day, when it is hottest out.