Extreme Heat

Heat kills by pushing the human body beyond its limits. Under normal conditions, the body's internal thermostat produces perspiration that evaporates and cools the body. However, in extreme heat and high humidity, evaporation is slowed and the body must work extra hard to maintain a normal temperature.

Most heat disorders occur because the victim has been overexposed to heat or has over-exercised for his or her age and physical condition. The elderly, young children and those who are sick or overweight are more likely to succumb to extreme heat.

Conditions that can induce heat-related illnesses include stagnant atmospheric conditions and poor air quality. Consequently, people living in urban areas may be at greater risk from the effects of a prolonged heat wave than those living in rural areas. Also, asphalt and concrete store heat longer and gradually release heat at night, which can produce higher nighttime temperatures, known as the "urban heat island effect."

Businesses in Florida especially those related to tourism, recreation, or construction should address extreme heat from a life safety perspective. Employees should be aware of heat disorders, know how to recognize the danger signals and avoid over-exposure.

Know the terms associated with extreme heat:

Heat wave - Prolonged period of excessive heat, often combined with excessive humidity.
Heat index - A number in degrees Fahrenheit (F°) that tells how hot it feels when relative humidity is added to the air temperature. Exposure to full sunshine can increase the heat index by 15 degrees.
Heat cramps - Muscular pains and spasms due to heavy exertion. Although heat cramps are the least severe, they are often the first signal that the body is having trouble with the heat.
Heat exhaustion - Typically occurs when people exercise heavily or work in a hot, humid place where body fluids are lost through heavy sweating. Blood flow to the skinincreases, causing blood flow to decrease to the vital organs. This results in a form of mild shock. If not treated, the victim’s condition will worsen. Body temperature will keep rising and the victim may suffer heat stroke.
Heat stroke - Heat stroke is life-threatening. The victim's temperature control system, which produces sweating to cool the body, stops working. The body temperature can rise so high that brain damage and death may result if the body is not cooled quickly.
Sun stroke - Another term for heat stroke.

Consider the following preparedness measures when faced with the possibility of extreme heat.

Install window air conditioners snugly, insulate if necessary.
Close any floor heat registers nearby and use a circulating or box fan to spread cool air.
Check air-conditioning ducts for proper insulation.
Install temporary reflectors, such as aluminum foil covered cardboard, to reflect heat back outside and be sure to weather-strip doors and sills to keep cool air in.
Cover windows that receive morning or afternoon sun with drapes, shades, awnings or louvers. Outdoor awnings or louvers can reduce the heat that enters a home by up to 80 percent. Consider keeping storm windows up all year.

See the Extreme Heat Safety Checklist (Checklist 12 in Appendix) and Disaster Supplies Kit (Checklist 2 in Appendix) for more information.