Heat Safety Information
What exactly is a heat wave?
A heat wave is a prolonged period of excessive heat and humidity. An Excessive
Heat Warning is issued if the heat index equals or exceeds 120° for
at least three consecutive hours. Excessive Heat Advisories are
posted when the heat index is expected to exceed 105° for two consecutive days
or if low temperatures are higher than 80°.
What is the Heat Index?
The heat index is a measurement of how hot it really feels when the relative
humidity is incorporated with the actual temperature. Heat indices were designed
for use in the shade with light wind conditions. If in direct sunlight, the heat
index can increase as much as 15°. With very hot and dry air, strong winds
can also be extremely dangerous.
| Category | Classification | Heat Index/Apparent Temperature (0F) | General Affect on People in High Risk Groups |
|---|---|---|---|
| I | Extremely Hot | 130° F or Higher | Heat/Sunstroke highly likely with continued exposure |
| II | Very Hot | 105° F - 130° F | Sunstroke, heat cramps, or heat exhaustion likely, and heatstroke possible with prolonged exposure and/or physical activity |
| III | Hot | 90° F - 105° F | Sunstroke, heat cramps, or heat exhaustion possible with prolonged exposure and/or physical activity |
| IV | Very Warm | 80° F - 90° F | Fatigue possible with prolonged exposure and/or physical activity |
What are the impacts of excessive heat?
As temperatures and humidity climb, the body has to work harder to maintain a constant temperature of 98.6°. Ninety percent of the body cooling process is done by evaporation of water through the skin, or sweating. Higher relative humidity slows the evaporation rate and cooling process. Heart rates increase trying to pump more blood through the body, that in turn, evaporates more liquids from the body. When the heat gain exceeds the level of heat the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body begins to rise and a heat related illness may develop.
Ranging in severity, heat disorders share one common feature: the individual has overexposed or overexercised for his/her age and physical condition.
Four types of heat disorders that occur and their symptoms include:
- Sunburn: Redness and pain. (also swelling, blisters, fever, and headaches)
- Heat cramps: Painful spasms usually in the legs and abdomen. (also heavy sweating)
- Heat Exhaustion: Heavy sweating and weakness, along with cold, pale, and clammy skin.
- Heat Stroke: A high body temperature, hot and dry skin, a rapid and strong pulse, and possible unconsciousness.
All heat disorders require attention, but heat stroke is a severe medical emergency and requires immediate medical attention. Any delays can result in death.
What can I do to stay safe during hot weather?
Following some simple safety tips can help prevent heat related problems:
- Stay out of the sun. (sunburn makes the job of heat dissipation more difficult)
- Spend as much time as possible in air conditioning. If you do not have an air conditioner, go to an air-conditioned public building, like a library.
- Slow down. (reduce, eliminate, or reschedule physical activities for a cooler time of the day)
- Drink plenty of water, even if you do not feel thirsty. Do not drink any alcohol, including beer.
- Dress in lightweight and light colored clothes. This will reflect the sunlight and heat.
- Eat smaller meals and less proteins.
- Do not take salt tablets unless specified by a physician.
