A healthy body temperature is maintained by the nervous system. As the body temperature increases, the body tries to maintain its normal temperature by transferring heat. Sweating and blood flow to the skin (thermoregulation) help us keep our bodies cool. A heat-related illness occurs when our bodies can no longer transfer enough heat to keep us cool.
A high body temperature (hyperthermia) can develop rapidly in extremely hot environments, such as when a child is left in a car in the summer heat. Hot temperatures can also build up in small spaces where the ventilation is poor, such as attics or boiler rooms. People working in these environments may quickly develop hyperthermia.
High temperature caused by a fever is different from a high body temperature caused by a heat-related illness. A fever is the body's normal reaction to infection and other conditions, both minor and serious. Heat-related illnesses produce a high body temperature because the body cannot transfer heat effectively or because external heat gain is excessive.
Heat-related illnesses include:
Often, environmental and physical conditions can make it hard to stay cool. Heat-related illness is often caused or made worse by dehydration and fatigue. Exercising during hot weather, working outdoors, and overdressing for the environment increase your risk. Caffeine or alcohol also increase your risk of dehydration.
Many medicines increase your risk of a heat-related illness. Some medicines decrease the amount of blood pumped by the heart (cardiac output) and limit blood flow to the skin, so your body is less able to cool itself by sweating. Other medicines can alter your sense of thirst or increase your body's production of heat. If you take medicines regularly, ask your doctor for advice about hot-weather activity and your risk of getting a heat-related illness.
Other things that may increase your risk of a heat-related illness include:
Most heat-related illnesses can be prevented by keeping the body cool and by avoiding dehydration in hot environments. Home treatment is usually all that is needed to treat mild heat-related illnesses. Heat exhaustion and heatstroke need immediate medical treatment.
Check your symptoms to decide if and when you should see a doctor.
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