COLUMBIA -- Scorching temperatures like those smothering the state this week led to the deaths of 24 people statewide in 1999.
Such a drastic toll hasn't been seen since that year when 21 people died during a three-week heat wave. But it could happen again.
So far, no deaths have been reported. Two to eight South Carolinians a year died because of the heat between 2000 and 2005. Counts for 2006 are not available from DHEC.
Though the dead in 1999 hailed from 17 counties, more than half were in the Savannah River basin.
Most were elderly -- almost two-thirds were in their 70s and 80s, according to DHEC records.
While the elderly are vulnerable to heat, they aren't the only ones. Four of the heat-related deaths in 1999 were of people in their 40s. And it might be surprising to learn what makes some people susceptible to heat-related illness.
Heat damages proteins called enzymes that the body needs to regulate various processes. In heat stoke, for example, the damage disrupts vital processes in the brain, leading to brain swelling, organ failure, coma and even death.
Mild heat exhaustion -- with symptoms of muddled thinking, nausea and headache -- can progress to heat stroke if untreated.
Recognizing heat-related illness can be tricky for doctors, as the symptoms can look like those of pneumonia, meningitis or other infections.
Knowing where and in what condition a patient was before being brought to the emergency department can help doctors diagnose correctly.
Once it is clear that heat is what landed someone in the hospital, doctors cool the patient off in a variety of ways, using a wet sheet, fans, ice bags on the underarms and groin, and a cooling blanket.
The body's cooling mechanisms don't work as well in the elderly as in the young. Losing heat from blood vessels close to the skin, for example, is hampered in the elderly since the heart doesn't pump blood around the body as strongly.
In addition, older people -- especially if they're sick -- might not realize when they are overheating. Some are unable to move themselves to a cooler spot. The same holds for the very young.
People with heart problems can overheat because of reduced blood flow in the body. And certain drugs, such as common antihistamines, antidepressants and antipsychotics, can make the body store heat.
Alcoholics are at increased risk of death from heat exposure. Drinking reduces a person's ability to sweat. In addition, drunken persons might not be aware enough to get themselves out of environments that are dangerously hot.
There is a limit to how much heat the body can lose in attempts to reach a safe body temperature.
When the body temperature has reached a certain high for an extended period, it can lose no more heat. That threshold, called a thermal maximum. can be easily reached when someone stays inside a hot, humid building for several hours.
"It's like you're stuck in a crock pot, you're not able to lose the heat through evaporation," emergency physician David Ford said.
A tepid -- not cold -- shower in the middle of the day can help ease the situation, Ford said. A cold shower will cause shivering, which produces heat.
People who are constantly in high-heat situations can build up some tolerance to heat in various ways, Ford said. The constant heat can lead to weight loss, which in turn lessens the amount of insulation under the skin, and improves the body's ability to lose heat. Also, those used to the heat can become more efficient sweaters, losing more water than salt. They also can build up shock proteins that help them stand the heat.
Ford recommends that people learn to listen to their bodies, and move to a cool place if they feel hot. Those who work outside during the summer should dilute an electrolyte drink to half-strength and sip it during the day; if urine is bright yellow, they should drink more.
Dee Hansen and her husband, Harry, a retired USC art professor, have been spending most of the hot days at home.
But come Thursdays, when Harry goes to adult day care at Morrill Alternative in West Columbia, Dee can't resist the lure of going trolling for antiques with longtime friend Sarah Edwards.
"Normally, I wouldn't put a foot out except to get the mail," she said.
The women have been going from town to town for the last three weeks, hopping from their car into antique shops and out again.
Hansen is careful to wear a hat and carry a water bottle. When she returns home, she keeps her cool there, too.
"I try not to run the air too much, but it's hard."
Reach Reid at (803) 771-8378.