Epidemiology Corner

August 16, 2002

Heat Related Illness

Summer in Houston is a challenge for many people who do not like hot weather. Unfortunately for many, the heat can be a cause of illness and on rare occasions, death. The human body is cooled by the evaporation of perspiration. When it is hot and humid (a normal summer day in Houston), the increased moisture in the air slows the evaporation of perspiration and the body is not able cool adequately. When this occurs it may result in one or more of the heat related illnesses. These include:

  • SUNBURN Redness and pain in the skin. When there is severe sunburn, there may be swelling, blisters, fever and headache.

  • HEAT CRAMPS Heavy perspiration and painful spasms usually in the legs or abdomen.

  • HEAT EXHAUSTION Perfuse perspiration, weakness, cold, clammy, pale skin. The pulse is thready and the person may faint and/or vomit.

  • HEAT STROKE/SUN STROKE High body temperature (106 oF or higher) with hot, dry, flushed skin, confusion and possibly loss of consciousness.

The people at greatest risk for developing heat related-illnesses are the elderly, the very young and those with underlying medical problems, including heart problems, diabetes and alcohol abuse, that exist prior to the onset of heat-related illness. A variety of activities are associated with morbidity including exercise, working and homelessness. When temperatures rise, the risk of heat-related illnesses also increases. From the city of Houston surveillance data, men are more prone to illness than women (63 percent of Houston cases are males).

Between 1979 and 1999, heat exposure caused 8,015 deaths in the United States. The Houston Health Department has done surveillance of heat-related illness since 1998. In the summer of 2000, 26 deaths involving Houston residents were reported. In 2001, 13 deaths were due to heat. There have been only four (4) deaths reported to our surveillance so far this summer. This smaller number of deaths is still of concern, because they could have been prevented.

To avoid heat-related illnesses stay indoors in air-conditioned areas when possible or if you have to go outside:

  • Use sunscreen (SPF-30 minimum), wear a wide-brim hat or use an umbrella.
  • Wear lightweight, light-colored, loose fitting clothes.
  • Drink extra water, juices and drink less tea, coffee, alcoholic and carbonated beverages.
  • If your home is not air-conditioned, go to facilities that are air-conditioned during the heat of the day, such as malls, libraries, multi-service centers and movie theaters.
  • Never leave a person or pet inside a closed car without ventilation.

Seek medical attention if you or someone you know develops any of the above symptoms during the approaching summer season.

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