Serious disorder that results from overexposure to heat. It is particularly common in people who do not enjoy perfect health (cardiac and vascular diseases, diabetes or alcoholism). The condition occurs mainly in hot damp weather and is caused by the failure of the heat regulation centres of the brain and the resultant overheating of the body. This may result in certain organs being damaged. The initial symptoms may be headache, dizziness and nausea. Sometimes there is a fit of epilepsy. Confusion or unconsciousness then sets in, and the blood temperature can rise to over 40°C. The liver and kidneys are often damaged by the high temperature. Damage to the heart and brain may also occur. A number of patients die from widespread tissue damage or shock. No time must be lost in treating the condition. The treatment consists of cooling the body as quickly as possible after the clothing has been removed. This may, for example, be done in an ice-bath. The patient must be taken to hospital so that all the vital functions can be monitored. After recovering, patients must avoid too warm an environment, because oversensitivity to heat can continue for a long time.