Heat exhaustion is a warning that your body can no longer keep itself cool. You might feel thirsty, dizzy, weak, uncoordinated, and nauseated. You may sweat a lot. Even though your body temperature stays normal, your skin feels cold and clammy. Some people with heat exhaustion have a rapid pulse. Rest in a cool place and get plenty of fluids. If you don’t feel better soon, get medical care. Be careful—heat exhaustion can progress to heat stroke.