Excessive Heat Safety

Heat is one of the leading weather-related killer in the United States, resulting in hundreds of fatalities each year. In the disastrous heat wave of 1980, more than 1,250 people died. In the heat wave of 1995 more than 700 deaths in the Chicago area were attributed to heat, making this the deadliest weather event in Chicago history. In August 2003, a record heat wave in Europe claimed an estimated 50,000 lives.

North American summers are hot; most summers see heat waves in one or more parts of the United States. East of the Rockies, they tend to combine both high temperatures and high humidity, although some of the worst heat waves have been catastrophically dry.

Heat Index Chart
Click on the chart below to view a text table of values.

Heat Index Chart - Click on the image to view a text table of values.

Our bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands, and as a last resort, by panting, when blood is heated above 98.6°F. Sweating cools the body through evaporation. However, high relative humidity retards evaporation, robbing the body of its ability to cool itself.

When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat related illnesses and disorders may develop.

The Heat Index (HI) is the temperature the body feels when heat and humidity are combined. The chart above shows the HI that corresponds to the actual air temperature and relative humidity. (NOTE: This chart is based upon shady, light wind conditions. Exposure to direct sunlight can increase the HI by up to 15°F.)

Never Leave Children, Disabled Adults or Pets in Parked Vehicles

Each year, dozens of children and untold numbers of pets left in parked vehicles die from hyperthermia. Hyperthermia is an acute condition that occurs when the body absorbs more heat than it can handle. Hyperthermia can occur even on a mild day. Studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, pets and even adults.  Leaving the windows slightly open does not significantly decrease the heating rate. The effects can be more severe on children because their bodies warm at a faster rate than adults. 

Safety Tips for Concerning Children

  • Make sure your child's safety seat and safety belt buckles aren't too hot before securing your child in a safety restraint system, especially when your car has been parked in the heat.
  • Never leave your child unattended in a vehicle, even with the windows down.
  • Teach children not to play in, on, or around cars.
  • Always lock car doors and trunks--even at home--and keep keys out of children's reach.
  • Always make sure all children have left the car when you reach your destination. Don't leave sleeping infants in the car ever

Safety Tips for Adults

  • Slow down. Reduce, eliminate or reschedule strenuous activities until the coolest time of the day. Children, seniors and anyone with health problems should stay in the coolest available place, not necessarily indoors.
  • Dress for summer. Wear lightweight, light-colored clothing to reflect heat and sunlight.
  • Put less fuel on your inner fires. Foods, like meat and other proteins that increase metabolic heat production also increase water loss.
  • Drink plenty of water, non-alcoholic and decaffeinated fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don't feel thirsty. Persons who have epilepsy or heart, kidney or liver disease, are on fluid restrictive diets or have a problem with fluid retention should consult a physician before increasing their consumption of fluids. Do not drink alcoholic beverages and limit caffeinated beverages.
  • During excessive heat periods, spend more time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, go to a library, store or other location with air conditioning for part of the day.
  • Don't get too much sun. Sunburn reduces your body's ability to dissipate heat.
  • Do not take salt tablets unless specified by a physician.

Heat Related Links

thermometer icon Heat: A Major Killer

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