Experts say heat can help your workout by boosting circulation and increasing flexibility. But it's also a relationship that can turn nasty.
A 2011 study by the CDC found heat-related illnesses that strike during a sport or recreational activity send nearly 6,000 people in the U.S. to ERs every year.
Sometimes the problem is not the heat but the humidity. If it's too humid , your sweat can't evaporate, and this can prove dangerous, causing a heat-related injury such as dehydration, heat cramps or heat stroke.
Experts say the key to beating the heat is adequate hydration before, during and after exercise.