Heat Index

Ever wonder what that "heat index" stuff is that weather people talk about? The heat index measures the temperature your body feels when heat is combined with humidity. This is sometimes called the THI (temperature-humidity index) or the discomfort index. (Remember that direct sunlight can increase these effective temperatures by 10 to 15 degrees).

Heat Index Risks

These are the risk factors:

• Less than 80 degrees--Comfortable by most standards
• 80 to 90 degrees--Moderate: fatigue with prolonged exposure and activity, use caution
• 91 to 100 degrees--Extreme: sunstroke, heat cramps, heat exhaustion possible
• 101 to 110 degrees--Hazardous: sunstroke, heat cramps, heat exhaustion likely
• Over 110 degrees--Dangerous: heat stroke possible

Remedies

Most things you need to do to stay healthy in the heat seem pretty obvious:

• Stay in air conditioning if possible
• If you must work outside, try to stay in the shade and avoid the hottest hours, noon to 6 pm
• Drink plenty of water
• Take plenty of rest breaks
• Wear light-colored, loose-fitting clothing
• Be aware of the warning signs of heat-related ailments

Take heat advisories and warnings seriously--your life may depend upon it.

Definitions

Heat exhaustion: marked by weakness, nausea, dizziness, and profuse sweating resulting from physical exertion in a hot environment. Sometimes called heat prostration.

Heatstroke: condition marked by cessation of sweating, extremely high body temperature and collapse that results from prolonged exposure to high temperatures.

Sunstroke: heatstroke caused by exposure to the sun.

Heat Index

This chart shows what the air feels like under different temperatures and humidity levels: