Heat illness

Heat illness is a result of your body temperature rising to a dangerous level during hot weather. It normally occurs from staying in the heat for too long without taking adequate measures to cool down.

Prevent heat illness

Take steps to prevent getting sick from the heat.

  • Remain in shaded or air-conditioned areas on hot and humid days.
  • Drink plenty of water if you have to be outside, especially during exercise.
  • Know the signs and symptoms of heat illness.

Be prepared for the heat

Humidity quickens the onset of heat illness. If you must be outdoors on hot and humid days, bring an adequate amount of water. Plan breaks in shaded areas and go indoors if you begin to feel unwell.

Warning signs of heat illness 

  • Symptoms of dehydration 
  • Cramping 
  • Unusual tiredness

How does heat illness occur?

Heat illness is a progressive illness that occurs when your core body temperature rises to unsafe levels. The illness begins with minor symptoms, such as rash and cramping, but if left untreated can lead to a life-threatening heat stroke.

The stages of heat illness

Heat illness onset can be gradual or sudden. Children, elderly, and the obese are the most susceptible to heat illness and should take the most precaution when it comes to being in high temperatures.

During heat alerts, make it a point to check on elderly neighbors to see they have adequate ventilation with fans or air-conditioning in their homes. Urge them to drink more than usual amounts of water and to stay indoors.

Illustration of heat illness

Heat illness affects everyone: you, your family, your neighbors, your customers.

PDF iconUse this one-page guide to spread awareness of the dangers of heat illness.
Last reviewed: 
June 2018
Alternative Names: 
Heat sickness

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