The result of prolonged exposure to hot temperatures, dehydration, or a failure of the brain to regulate the body's temperature. People that work in the heat, especially with high humidity, and do not drink enough fluids can experience heat exhaustion. If they do not get out of the heat and get appropriate treatment heat exhaustion can progress to heat stroke. Heat stroke is a life threatening emergency and can lead to permanent brain and kidney damage. The conditions that increase the risk of this disorder are being very young or very old, obesity, other chronic health problems, not being used to working the heat, and drinking alcohol.