Hot Enough for Ya?
Interpreting the heat index so you really can know
(HealthDay is the new name for HealthScoutNews.)
SATURDAY, July 5, 2003 (HealthDayNews) -- Approximately 385 Americans die from the heat every year and many thousands of others suffer a heat-related illness, according to the U.S. Centers for Disease Control and Prevention.
Knowing about the heat index can keep you and your loved ones from becoming one of those statistics this summer.
The heat index is a measure of how hot it is once the temperature and humidity are taken into consideration, says Jim Angel, the Illinois State Climatologist based in Champaign.
"This index comes from biometerological studies that account for body size, core and body surface temperatures, clothing, the skin's resistance to heat and moisture transfer from the body," Angel explains. "It is based on an average-sized adult wearing clothing in the shade, with a 5-mile-per-hour wind. Being in full sun or in an area with little air movement will make the apparent temperature feel even hotter."
Heat disorders, including heat cramps, heat exhaustion and heatstroke (also called sunstroke), are closely related to the heat index.
When the index values are between 80 and 90, heat fatigue is possible with prolonged exposure and/or physical activity.
When index values are between 105 to 130, sunstroke, heat cramps and heat exhaustion are possible with prolonged exposure and/or physical activity.
When index values are above 130, all heat-related disorders are likely with continued exposure.
When the index starts to rise, experts advise those who don't have access to air conditioning to be particularly careful by drinking plenty of liquids, even if you don't feel thirsty; avoiding strenuous outdoor activity; wearing loose-fitting, lightweight and light-colored clothes; using sunscreen and wearing a hat; keeping shades drawn and blinds closed, but windows slightly open; and taking cool baths or showers and using cool, wet towels to cool down.
"Spending even two hours a day in an air-conditioned space can significantly reduce the risk of heat-related illness when the heat index is high," Angel says.
The National Weather Service has additional information about the heat index and heat disorders.