These substances drain the body of needed fluids. Seek medical help if the victim does not improve. The cause of heat exhaustion is excessive exposure to heat and humidity with body fluids being lost through heavy sweating. Blood flow to the skin increases, causing blood flow to decrease to vital organs. This puts a strain on the heart and circulatory system.
Mild shock can result.
If untreated, a person's condition will worsen leading to heat stroke. Nausea or vomiting. Move victim to a cool or shady area. Have victim rest in a comfortable position. Remove or loosen tight clothing.