A heat wave is a period of excessive heat lasting two days or more that leads to illnesses and other stresses on people with prolonged exposure to these conditions. High humidity, which often accompanies heat in Missouri, can make the effects of heat even more harmful. While heat-related illnesses and death can occur due to exposure to intense heat in just one afternoon, heat stress on the body has a cumulative effect. Consequently, persistence of a heat wave increases the threat to public health.

WHO IS MOST VULNERABLE DURING A HEAT WAVE?

The elderly population is the most vulnerable to the dangers of heat. Of the 522 deaths that occurred in Chicago during the July 12-16, 1995 heat wave, 371 (73 percent) were 65 or older. The elderly suffer due to the diminished ability to perspire. Since the function of perspiration is to provide evaporation, which in turn provides cooling, the elderly have a reduced capacity to release heat from the body.

In addition to the elderly, infants, young children, and people with chronic health problems (especially preexisting heart disease) or disabilities are more vulnerable to the effects of heat waves. People who are not acclimated to hot weather, overexert themselves, are obese, or use alcohol or drugs (including drugs such as antipsychotics, tranquilizers, antidepressants, certain types of sleeping pills, and drugs for Parkinson's disease) are at great risk.

WHAT CAN YOU DO TO LESSEN THE ADVERSE EFFECTS OF HEAT?

Before the heat wave begins:

Check NOAA Weather Radio (tuned to either 162.525 mhz or 162.550 mhz in Franklin County), other radio sources, TV, or cable TV to obtain the latest forecast and plan outdoor activities accordingly.
If excessive heat is forecast, plan to go to a place to cool off if you don't have air conditioning. Find out if your community offers schools, libraries, park buildings, shelters, or other places to seek refuge from the heat. Plan to spend time at the library, shopping mall, or with friends or neighbors.
Check on elderly family members and make any necessary contingency plans to provide them with comfortable shelter. Have those with blood circulation problems or other chronic problems requiring regular use of medications check with their physician to discuss how to handle the hot conditions.
Those who supervise outdoor workers or student activities should review heat wave safety guidelines and adjust the intensity and duration of activities accordingly.
During the heat wave:

Drink plenty of water and natural fruit juices, even if you're not thirsty.
Avoid alcoholic beverages and drinks with caffeine, such as coffee, tea, and colas.
Wear loose-fitting, lightweight, light-colored clothing.
Avoid going out during the hottest times of the day.
If you must go out, use sunscreen and wear a wide-brimmed hat. Remember that sunburn reduces the skin's ability to provide cooling.
Using a buddy system between coworkers in high heat-stress jobs can help ensure that signs of heat stress do not go unnoticed.
If air conditioning is unavailable: During the day, keep shades drawn and blinds closed, with windows open slightly. At night, open windows .
Keep lights down low or turned off.
Take cool (not icy cold) baths or showers.
Eat frequent, small meals. Avoid high protein foods, which increase metabolic heat. Fruits, vegetables, and salads constitute low protein meals.
Avoid using salt tablets unless directed to do so by a physician.
Don't leave children or pets in a closed vehicle with the windows up. Temperatures inside a closed vehicle can reach over 140 degrees within minutes.
The best way to beat the heat is to spend time in air conditioning. Even just two hours per day in air conditioning can significantly reduce the risk of heat-related illness.
Provide extra water and access to a cool environment for pets.
Listen to media sources to keep up with the latest heat watches, warnings, and advisories.

Heat Disorder
Symptoms
First Aid
Heat Cramps Painful spasms usually in muscles of legs and abdomen due to heavy exertion. Heavy sweating. Stop activity and rest in a cool place. Lightly stretch or gently massage muscle to relieve spasms. Give sips of cool water.
Heat Exhaustion Heavy sweating. Skin cool, pale, and clammy. Pulse fast and weak. Breathing fast and shallow. Fainting, dizziness, vomiting, and nausea. Get victim to a cool place. Have him lie down and loosen clothing. Apply cool, moist cloths. Give sips of cool water.
Heat Stroke

(Also called "sun stroke")
Temperature 103 or higher. No sweating, rapid pulse, fast and shallow breathing. Hot, red, dry skin. Nausea, dizziness,headache, confusion. Heat stroke is a SEVERE medical emergency. Summon emergency assistance or get the victim to a hospital immediately. DELAY CAN BE FATAL! While waiting for emergency medical assistance, move the victim to a cooler environment. Use cool baths or sponging to reduce body temperature.

MEASURING THE COMBINED EFFECTS OF HEAT AND HUMIDITY

The National Weather Service uses the heat index to compute the "apparent temperature" which is a measure of how hot it feels to people at a certain combination of temperature and humidity. The heat index values used in forecasts, advisories, and warnings assume an average size adult with light clothing in the shade with a 5-mile-per-hour wind blowing. Being in full sun or in an area with little air movement can increase the apparent temperature and thus the risk for adverse effects from the heat and humidity. Winds greater than 5 miles per hour usually enhance evaporative cooling and decrease the apparent temperature and health threat from the heat. As noted, the effects of heat are cumulative over time. The greatest number of heat-induced illnesses and fatalities usually peak two days after the maximum heat index values occurred.