The sun's out, the mercury has climbed out of the 80's and it seems like the perfect day for a run in the park. So why do you feel like you're running through molasses?
When temperatures rise, your athletic performance usually takes a dip, until you acclimate to the new outdoor realities.
When it's hot out, your body has to pump more blood to the skin's surface where heat is released. When this happens, however, there's less blood available to serve the working muscles. It's like the lone customer service rep who's trying to answer phone calls and deal with a long line of people in front of him. It's just not a high-performance setup. On top of that, your heart rate increases and your sense of exercise strain goes up.
Fortunately, when your body "calls for backup," it makes some impressive physiological changes that let you handle the heat better within 10 to 14 days. Some of the adaptations happen in just five days.
Over time, "you improve your ability to maintain cardiovascular function, meaning that the heart deals with the heat better and you improve your ability to dissipate heat into the environment," says Lawrence Armstrong, Ph.D., professor of environmental and exercise physiology at the Human Performance Laboratory at the University of Connecticut, Storrs. Here are several pieces of advice he recommends knowing to avoid common pitfalls when triathlon training in hot weather.
Which Changes Happen Fastest?
Within the first three to six days of working out in the heat, your body actually makes more blood to better serve both the muscles and the skin. As you get used to the heat, your plasma volume goes back to where it was before.
According to Armstrong's study The Induction and Decay of Heat Acclimatization in Trained Athletes,in that first week your heart rate during hot exercise will likely decrease, and the feeling that you're working harder than usual should drop, too.