Here’s what happens to your body in extreme heat, what you need to watch out for and how to stay safe. And if your environment is hot and humid, sweat doesn’t evaporate as easily – which pushes your body’s temperature even higher, according to the Mayo Clinic. “The higher the humidity, the lower temperatures you need for extreme heat,” Linden said. High body temperatures can lead to damage to the brain and other vital organs, the CDC says. Try to find air conditioning, or places in your area where you can go to stay cool, according to Ready.gov.