From 1979 to 2003, more than 8,000 people died from exposure to excessive heat in the United States, according to the Centers for Disease Control and Prevention. More people died from heat during that period than from hurricanes, lightning, tornadoes, floods, and earthquakes combined.
People who are in good shape deal better with the heat, because they sweat sooner and more and they have better blood flow to the skin. But even if you’re healthy and fit, exercising in the heat can push you over the edge.
Experts recommend drinking plenty of fluids and exercising indoors on the hottest days. Hit the trails or pound the pavement at the coolest time of day, usually in the early morning. And watch for your area’s heat index, which combines temperatures with humidity levels to give a more accurate idea of how your body will respond to the day’s conditions.