He or she collapses, sweating profusely. A person suffering heat exhaustion displays many of the symptoms of shock, such as faintness, headache and nausea. In most cases, the body temperature remains about normal. Heat exhaustion is the body's response to the loss of water and salt from sweating. Rest in a cool, shaded environment, along with fluid and salt replacements.
Victim looks flushed and has hot, dry skin.
Heatstroke is more serious than heat exhaustion. A person suffering from heatstroke feels hot but cannot sweat. The body temperature rises so high that it can cause brain damage if not lowered quickly. Symptoms include mental confusion, delirium, headaches and dizziness. It is a major medical emergency.