By Robert King — Daily Staff Writer

When working or playing in the hot sun, there are ways to tell if you need a cool drink of water — or a ride to the hospital.

Learning the symptoms of heat-related illnesses is an important part of treatment and prevention during the hot summer season.

The two most severe types of heat-related illnesses are heatstroke and heat exhaustion.

Heatstroke is the more serious of the two, and can be life-threatening.

The illness occurs when the body is unable to regulate its temperature, according to information from the national Centers for Disease Control and Prevention in Atlanta.

Symptoms include an extremely high body temperature, red, hot and dry skin, dizziness and nausea, according to the CDC.

The body also loses its ability to sweat and cool down.

Heatstroke requires immediate medical attention. Medical professionals use different ways to cool the body down.

"We cool them down with [intravenous] fluids. We have a cooling blanket that we can use too," said Ruth Ann LaFever, a registered nurse who works in the emergency room at Warren Memorial Hospital in Front Royal.

The most common form of heat-related illness is heat exhaustion, which is less severe than heatstroke.

"Heat exhaustion is the milder form, and can form over several days of exposure to higher temperatures [and] if [you] don't replace fluids," said April Jenkins, nurse manager for the Lord Fairfax Health District. "The pulse could be very fast or very weak, [and] the skin is cool and moist."

Other symptoms that identify heat exhaustion include fainting, nausea, vomiting, weakness, tiredness and muscle cramps.

A way to help treat heat exhaustion is to drink plenty of fluids, Jenkins said.

"Basically that is to replace the salt and minerals they have lost from sweating," she said.

Heat exhaustion is the most common heat-related illness LaFever said she sees in the emergency room.

Another common heat-related illness are heat cramps, which occur when a person sweats profusely during physical activity.

A painful muscle cramp can occur if the body is depleted of salt and fluid, according to information from the Virginia Department of Health.

Muscle cramps in the stomach, legs or arms are symptoms, according to the VDH. Treatment involves resting for several hours and drinking juice or sports beverages. Medical treatment is needed if the heat cramps haven't subsided in an hour.

The most common victims of heat-related illness LaFever said she sees are construction workers and people performing outdoor activities for long periods of time.

"The elderly at home without the air conditioning are the most critical," she said. "They can really have heart damage and really get dehydrated."

Children age 4 and under, people who are overweight or overexert themselves by work or exercise are also at risk, according the VDH.

There are many ways to prevent heat-related illnesses.

The health district warns residents of extreme heat conditions and what to do to prevent illness, Jenkins said.

Staying in an air-conditioned area is a vital way to beat the heat, she added.

Sometimes an electric fan might not be enough, the VDH warns.

"At temperatures in the high 90s or above, a fan may not prevent heat-related illness," according to the VDH. "Spending at least two hours per day in air conditioning significantly reduces the number of heat-related illnesses."

Jenkins said if residents don't have air conditioning they need to find an air-conditioned public place.

"If you don't have an air-conditioning source, then maybe you could go to a local mall or library," she said.

If you have to go outside, plan activities around the heat, the VDH warns.

"If you do have to plan outdoor activities, try to plan it to do it early in the morning before the sun is at its hottest at noon or early evening," Jenkins said.

Also, make sure to wear light clothing and sunscreen and drink plenty of fluids to replace salt and minerals lost from sweating, Jenkins added. The VDH recommends drinking two to four glasses of a cool fluid an hour.

Residents on a fluid-restricted diet or on diuretics, a drug that elevates the rate of urination, should ask their doctor before performing activities in the heat, according to the VDH.

The VDH also recommends not leaving any pets or children in cars with the windows rolled up, even partially.

"Temperatures inside a car can reach [more than] 150 degrees quickly, resulting in heat stroke and death," the VDH warns.

* Contact Robert King at rking@nvdaily.com