Too much of a good thing is usually detrimental. Soaking up too much sun can be life-threatening if you don't know how to prevent and treat heat-related conditions. Find out how you can stay cool as the temperatures rise.

Too much of a good thing is usually detrimental. And soaking up too much sun can be life-threatening if you don't know how to prevent and treat heat-related conditions.

Whether at work or play, extended periods in the sun can leave a person feeling tired, dehydrated and weak. The summer sun's rays are silent predators, slowly wearing down the body with each hour spent outdoors.

Left untreated, conditions such as heat exhaustion may progress to more severe illnesses, such as heat stroke, leading to hospitalization and even death.

Now that summer is here, this is what you need to know to stay safe during the hottest days of the year.

Heat exhaustion vs. heat stroke

Dr. Christopher L. Gleason, associate professor of family and consumer medicine at Southern Illinois University School of Medicine, says heat exhaustion occurs when heat and humidity cause a person's core body temperature to rise through exertion, or when the person spends an extended period in intensely heated conditions.

Heat exhaustion results in a rise in the core body temperature to between 100 and 104 degrees.

Heat stroke, a severe form of heat exhaustion, affects a person's cooling system, which is controlled by the brain, Gleason says. The body's core temperature rises to 105 degrees or more.

When the body's cooling system ceases to function, a person stops perspiring, causing internal body temperatures to rise. That can result in brain damage and damage to other internal organs. People taking antihistamines or allergy, blood pressure and depression medications are often predisposed to heat stroke because chemicals in the medications impair the body's ability to sweat.

Gleason said classic heat stroke results from chronic medical conditions, such as heart disease, that keep a person from controlling his or her body temperature in hot environments. Exertion heat stroke occurs when someone overdoes it while playing or exercising outside.

Warning signs

Individuals with heat exhaustion can experience a wide range of symptoms, including:

- Pale, cool and moist skin
- Cramps and/or muscle pain
- Headache
- Weakness
- Nausea and/or dizziness
- Thirst
- Increased pulse

The signs of heat stroke include confusion, hallucinations and dizziness. A heat stroke victim's skin is usually flushed, hot and dry, although it may initially be moist from perspiration. Slightly elevated blood pressure, hyperventilation and coma are severe symptoms that require emergency attention.

Seek immediate medical attention if someone shows these symptoms:

- Deteriorating mental status
- Inability to keep fluids down
- Continuous vomiting
- A rising temperature despite attempts to cool the person
- Heat exhaustion accompanied by other serious ongoing medical problems.

Who's at risk?

The very old and very young are prime targets for heat stroke.

Gleason says senior citizens who are unable to change their environment are especially prone to heat stroke fatalities.

"Seniors in wheelchairs or the elderly who are bedridden cannot move themselves to a cooler place. A lot of them may not have fans or air conditioning. As a result, they may become severely overheated and die sitting in their chairs," he says, citing the severe 1996 Chicago heat wave during which dozens of senior citizens were found dead in their homes.

Infants and toddlers are at risk because their bodies take longer to cool off than adults.

Heat-related illnesses also attack those who spend extended periods of time outdoors -- even if they are not exerting themselves. People who sunbathe or sit and read for long periods in extreme heat may suffer from heat exhaustion or stroke. Gleason says humidity can contribute to a higher heat index that makes performing even simple outdoor activities hazardous.

"If the heat index is in the mid-to upper 90s, the sun doesn't have to be shining for a person to incur heat exhaustion," Gleason says. "Temperatures in the upper 80s or 90s on humid, overcast days are prime conditions for people to develop heat-related illnesses."

Self-care at home

You can treat mild forms of heat exhaustion at home. recommends resting in a cool, shaded area and drinking cold water or sports drinks. Gleason says low-sugar sports drinks (6 percent or less glucose) with high amounts of electrolytes, along with salty snacks, help replenish the salt the body has lost through perspiration.

You should also loosen or remove clothing and apply cool water to the skin.

Move victims of heat stroke to a cool environment or have them sit in a tub of lukewarm water before an ambulance arrives.

Gleason recommends placing ice packs in the armpits or groin and using a fan to blow cool air across the skin while administering cool beverages "only if the person has a normal mental state. Treatment is aimed at reducing the patient's core temperature to normal as quickly as possible."

Ounce of prevention

Avoid heat exhaustion by limiting strenuous activity in hot, humid environments.

Construction workers, landscapers, lifeguards, children who play outdoors and others who are outside a lot should intersperse periods of rest into their day with plenty of cold fluids, Gleason says.

"Avoid activity as much as possible during the hottest parts of the day, between 10 a.m. and 3 p.m.," he recommends. "Wear light-colored, loose-fitting clothing and wide-brimmed hats. Use common sense and play it smart."

State Journal-Register (Springfield, Ill.)