Heat rash disappears when the person is returned to cooler temperatures. Infection can occur if the problem is not corrected. This is helped by replacing the lost salt and electrolytes, usually taken together with lots of water as well. Fainting due to heat is caused by the same factors that cause other fainting. People most likely to faint in the heat are those unused to working in it.
Heat exhaustion is caused by excessive sweating.
Nausea, giddiness, thirst and headache are common symptoms of this problem. Body temperature may or may not be higher than normal. People vary widely in how much tolerance they have for heat, making it sometimes difficult to foresee this problem. Treatment includes cooling the victim and giving liquids. Take the victim to a cool place, resting in a head-low position.