Heat stress causes heat-related illness by affecting your body's ability to cool down properly. The body normally cools itself by sweating, but sweating just isn't enough under some conditions. In such cases, a person's body temperature rises rapidly. Very high body temperatures may damage the brain or other vital organs.

Heat-related illness includes a range of health impacts from milder conditions like heat rash and heat cramps to the most common type, heat exhaustion. The most serious heat-related illness is heat stroke. Heat stroke can cause death or permanent disability if emergency treatment is not provided.

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An extreme heat event, or heat wave, is an extended period of time (several days or more) with unusually hot weather conditions that can potentially harm human health. When temperatures increase, communities across the United States are vulnerable to heat-related illnesses which may lead to heat stroke and death.

Anyone can develop heat stress. However, the following groups of people have higher risks of experiencing heat stress or heat-related death:

  • Infants and children up to four years of age,
  • People 65 years of age and older,
  • People who are overweight, and
  • People who are ill or on certain medications

Preventing Heat-related Illness

Several factors affect the body's ability to cool itself during extremely hot weather. When the humidity is high, sweat will not evaporate as quickly and prevents the body from releasing heat quickly. Other conditions related to heat illness risk include age, obesity, fever, dehydration, heart disease, mental illness, poor circulation, sunburn, and prescription drug and alcohol use.

Heat-related death or illnesses are preventable if you follow a few simple steps.

  • Stay in an air-conditioned area during the hottest hours of the day. If you don't have air conditioning in your home, go to a public place such as a shopping mall or a library to stay cool. Cooling stations and senior centers are also available in many large cities for people of all ages.
  • Wear light, loose-fitting clothing.
  • Drink water often. Don't wait until you are thirsty.
  • Avoid unnecessary hard work or activities if you are outside or in a building without air conditioning.
  • Avoid unnecessary sun exposure. When in the sun, wear a hat, preferably with a wide brim.

Air conditioning is the strongest protective factor against heat-related illness. Exposure to air conditioning for even a few hours a day will reduce the risk for heat-related illness.

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