MOODY AIR FORCE BASE, Ga. -- Overestimating the ability to withstand hot weather can happen even to those acclimatized to the heat and humidity of South Georgia.

A better indication of the total effect temperature, humidity, wind speed and solar radiation has on humans is the wet bulb globe temperature. It expresses the combined effect that humidity and high temperature has on the body. Discomfort begins to occur when the WBGT is around 86 degrees and steadily becomes worse as the temperature rises.

As the WBGT gets above 95 degrees, it becomes harder and harder for sweat to evaporate, preventing the body from releasing heat and efficiently cooling itself. In this environment, it does not take long before one starts to experience symptoms of heat-related illnesses.

Heat stroke is the most severe of all heat-related illnesses. It can occur suddenly when one is overly exposed to intense heat or sun and not adequately hydrated, or it may arise from heat exhaustion. At this point, the body has exhausted all of its reserves of water and salt and sweating has stopped.

The skin is red, hot, and dry as the sweating mechanism is no longer able to cool the body. The body's core temperature rapidly rises above 99 degrees. Emergency medical intervention is critical at this point to prevent serious or irreversible injuries. Other symptoms include fast pulse, throbbing headache, dizziness, nausea, confusion and unconsciousness.

Heat exhaustion is a milder form of heat-related illness. It can result from significant dehydration caused by inadequate fluid intake or excessive loss of water and minerals by means of heavy perspiration. Heat exhaustion often occurs after several days of exposure to heat or after prolonged physical exertion in very hot weather, causing a collapse of the body's cooling system.

The skin is pale, cool, and clammy. The pulse rate is fast and weak and breathing is fast and shallow. Other symptoms include profuse sweating, weakness, dizziness, intense thirst, blurred vision, nausea, muscle cramps and headache. If left untreated, heat exhaustion can quickly progress to heat stroke. The initial first-aid step is to remove the victim from work or training, and allow the person to rest in the shade or cool area, and provide sips of water.

Heat cramps usually affect people who sweat a lot during strenuous activity. Profuse sweating depletes the body's salt and moisture, reducing the levels of salt in the muscles. Heat cramps are muscle pains or spasms that are usually in the abdomen, arms or legs. The crampst may occur in association with strenuous activity. Heat cramps may also be a symptom of heat exhaustion. Medical attention is usually not necessary.

It is best to stop all activity, sit quietly in a cool place and hydrate with a sports beverage. Refrain from strenuous activity for a few hours after the cramps subside, because further exertion may lead to heat exhaustion or heat stroke. Seek medical attention if the cramps do not subside in one hour.

It is very important to take proper precautions during times of extreme heat and humidity to prevent the likelihood of succumbing to a heat-related illness. Prevention is the key. The following measures can help avoid heat related injuries.

- Drink plenty of fluids: Increase your fluid intake, regardless of your activity level. In hot environments, it is possible for the body to lose one liter of fluid per hour. Don't wait until you're thirsty to drink. Thirst is not a good indicator of fluid loss.

-Replace salt and minerals: Heavy sweating removes salt and minerals from the body. These are necessary for your body and must be replaced. The working muscles are most likely to be affected, during or after exercise. Adding sports beverages to your fluid intake can help to replace the salt and minerals lost from sweat.

- Be aware of your environment: If you work in the heat or around heat sources, take whatever steps necessary to control the heat externally. If you must be outdoors, try to limit activities to the early morning and evening hours. Try to rest often in shady areas so that your body's thermostat will have a chance to recover.

- Take frequent breaks: Pace yourself, start slowly and pick up the pace gradually. As the temperature increases, more frequent breaks are needed to stay cool.

- Wear proper clothing: Loose, lightweight fabrics encourage heat release and reflect sunlight.

- Acclimatize: It takes at least seven to 10 days to get used to working in a hot environment.

- Stay cool indoors: Air-conditioning is the number one protective factor against heat-related illness and death. If a home is not air-conditioned, go to the shopping mall or public library- even a few hours spent in air conditioning can help the body stay cooler when returning to a hot environment.

- Stay in shape: A healthy heart and good muscle tone work more efficiently and generate less heat.

- Eat light during the workday: Hot, heavy meals add heat to the body and divert blood flow to aid with digestion.

- Be aware of special heat stress risk: Caffeine, alcohol, diabetes or medications for high blood pressure and allergies can increase the risk of heat stress.

- Monitor those at high risk: The elderly, the very young, and those with mental illness or chronic diseases are at highest risk. However, even young and healthy individuals can succumb to heat if they participate in strenuous physical activities during hot weather.

- Never leave infants, children or pets in a parked car, even if the windows are cracked open: Cars can heat up to dangerous temperatures very quickly. Even with the windows cracked open, interior temperatures can rise almost 20 degrees Fahrenheit within the first 10 minutes. Anyone left inside is at risk for serious heat-related illnesses or even death.

- Use sunscreens that provide a minimum sun protective factor of 15 to protect against ultraviolet A and UV B. Unprotected exposure to the sun can cause sunburn and accelerates skin aging. It may also cause drug photosensitization and depress skin immune responses. Sunburn also increases the risks of skin cancer, basal and squamous cell carcinomas on exposed areas, and melanomas anywhere on the body.