What Happens To Your Body When You Exercise In The Heat

When the temperature heats up outside, it's normal for a relatively easy workout to suddenly feel incredibly hard, as your body struggles to cool down from both the exertion and the temperatures outside. Good news: It's rarely dangerous to work out in hot temperatures, but there are a few precautions you should take and warning signs to keep in mind.

Our bodies are pretty smart, and can regulate our effort while also kickstarting cooling mechanisms, like sweating, which allows heat to dissipate from the body. Even on cooler days, our metabolism is working during exercise largely because it's trying to control body temperature and keep it stable. Add in a hot day, and the body has to work a lot harder (via the National Academies Press).

As you sweat, your body loses both fluids and electrolytes, which are critical for both athletic performance and general health. (That's why sweat tastes salty: You lose water and sodium, among other key electrolytes.) During hot workouts, staying hydrated with water and electrolytes is critical, especially as volume or intensity increase (via Men's Journal).

Is temperature all that matters?

Humidity can make matters even worse. Typically, when sweat evaporates off of your body, it produces a cooling effect. But when you're sweating in a high humidity environment, that sweat sticks around. "That's why high humidity is a challenge — you can be sweating a lot but that sweat isn't evaporating, so you're just getting dehydrated and it's dripping off your body and making you feel uncomfortable," Stephen S. Cheung, Ph.D., a kinesiology professor and expert on heat and exercise, told Self.

In any hot condition, athletes should be mindful of symptoms of heat exhaustion and heat stroke, which can happen when the body's core temperature gets too high. Heat cramps in your muscles are common easy early warning signs telling you to slow down and cool off. But other signs of heat-related illness during exercise can include nausea, weakness, sudden fatigue, headaches, confusion, and an increase in your heart rate. If this happens, cooling off and getting help are incredibly important: Don't try to push through the pain (via the Mayo Clinic).