Are you training in the heat? Read this article for some great tips on how to do it safely.
Many runners are going out for their morning runs, even in our 100+ heat we suffered through last week. While it is important to stay properly hydrated, running in high humidity with high ozone levels can be dangerous and make you feel winded and out of energy, even if you are in an air conditioned building.
Running Times magazine offers some sound advice for those who want to go out when it is hot.
Training in the Heat
Why you’re slower in the summer and what to do about it
Thermoregulation is how your body maintains a consistent internal temperature. When exposed to external heat, your body cools itself and maintains equilibrium via perspiration. Perspiration has a cooling effect on the body because it removes excess heat through evaporation. The rate of evaporation–and subsequently how well the body is cooled–changes depending upon humidity. When humidity is low, evaporation increases; when humidity is high, the rate of evaporation decreases and less cooling occurs.
Sweating, while critical to cooling the body, leads to fluid loss. Dehydration from fluid loss has a profound effect on running performance–a loss of even 2 percent of body weight leads to about a 4-to 6-percent drop in performance. Furthermore, both temperature and humidity increase heart rate and amplify these effects. At 60 to 75 degrees, heart rate increases by two to four beats per minute. From 75 to 90 degrees, heart rate increases up to 10 beats per minute, and humidity increases it even more. Perceived effort is accordingly much greater as both the temperature and the humidity rise.