What happens to the muscles when we exercise in hot weather?

When you exercise, the working muscles in your body create heat, which is transported around the body by your blood. As your body temperature increases, the blood vessels near the skin open up and the sweat glands work harder. If you want to increase your muscle strength, doing workouts in the cold probably won't help. Muscles work best at hot temperatures. When muscles get cold, the force they can produce decreases. You are also more likely to get injured in the cold, but the extra risk of injury is reduced if you warm up properly. Whether you're running, playing a pickup game of basketball or going for a power walk, take care when the temperature rises. If you exercise outdoors in hot weather, use these commonsense precautions to prevent heat-related illnesses.

How heat affects your body

Exercising in hot weather puts extra stress on your body. If you don't take care when exercising in the heat, you risk serious illness. Both the exercise itself and the air temperature and humidity can increase your core body temperature.

To help cool itself, your body sends more blood to circulate through your skin. This leaves less blood for your muscles, which in turn increases your heart rate. If the humidity also is high, your body faces added stress because sweat doesn't readily evaporate from your skin. That pushes your body temperature even higher.