News of seniors succumbing to summer's sizzling heat sends shock waves across the country, but chilly air can prove just as deadly for older adults. How does aging alter your ability to endure seasonal extremes?

Withstanding hot and cold weather and regulating body temperature become more challenging as people grow older. Medications, chronic ailments and entrenched habits contribute to increased risk of heat disorder (hyperthermia) and cold disorder (hypothermia).

"At age 40 we have more physiological reserves to help us deal with changes in temperature," says gerontologist Terrie T. Wetle, PhD, deputy director of the National Institute on Aging. "Some physical changes associated with aging put us at higher risk."

In addition to physical changes, lifelong habits and finances add to the problem. For example, many seniors don't feel safe opening windows and hesitate to use the air conditioner or heater due to the cost of electricity. Seniors also tend to wear long-sleeve, dark, synthetic clothes, which hold in heat and don't breathe.

Body Temperature Regulation

The body primarily cools through perspiration. As moisture on the skin evaporates, the body cools. Core temperature remains stable as long as fluid and salt are replenished. But if dehydration occurs, the body tries to conserve fluid loss by ceasing sweating.

"In order to perspire we have to have fluid on board," Dr. Wetle explains. "[But] older people begin to lose their sense of thirst. By the time an older person is feeling thirsty, he is already quite dehydrated."

"Another contributing factor [for temperature-related disorders] in many older people is a change in the sensation of temperature," Dr. Wetle says. "This may be due to changes in the skin, a thinner layer of fat just below the surface of the skin, or to changes in the actual sensation of heat or cold."

In cold temperatures, the body attempts to keep warm by shivering. Thyroid conditions, circulatory ailments, strokes, dementia, decreased mobility, medications and alcohol all impede an older person's ability to keep warm.

Several other factors can make controlling body temperature difficult:

  • Humidity hinders the cooling process, because perspiration doesn't evaporate as quickly.
  • Conditions that alter blood circulation, such as high blood pressure, and inefficient sweat glands have an impact on temperature control, as does lack of conditioning.
  • Sedatives and tranquilizers may also decrease the body's ability to cool down.
  • Diuretics or water pills increase the risk of dehydration.

Warning: Never change a medication before consulting your physician.

Heat-related Illnesses

A body that stops cooling creates a medical emergency. According to the Centers for Disease Control and Prevention, an average of 400 Americans die every year from heat-related conditions. The majority (61%) are over 55 years of age.

Heat fatigue - the feeling of weakness after exposure to high temperatures. People may feel faint with cool, moist skin and a weak pulse.

Heat syncope - usually occurs after exercising in the heat. The person suddenly feels dizzy. The skin becomes pale, moist and cool, the pulse weak and rapid.

Heat cramps - painful muscle spasms after strenuous activity; can also be a sign of ]]>heat exhaustion]]> .

Heat exhaustion - occurs when the body becomes too hot. Thirst, weakness, fatigue, nausea and profuse sweating serve as warnings. If treatment is delayed, heat exhaustion can advance to deadly heat stroke.

Heat stroke - can occur within 10 or 15 minutes. Symptoms of this potentially lethal rise in body temperature include confusion; bizarre behaviors; a strong, rapid pulse; dry, flushed skin with no sweat; headache or nausea.

First aid for heat-related illnesses includes moving to a cool, shady place; offering cool liquids, if able to swallow; packing in ice, if possible; and calling for medical assistance.

Preventing Heat Illnesses

Several seemingly effortless actions can prevent these heat emergencies.

"We suggest that older persons drink water or a fruit juice on a regular schedule rather than waiting until they feel thirsty," says Dr. Wetle. Avoid beverages containing alcohol and ]]>caffeine]]> , which act as diuretics and deplete needed fluid. Do not take salt tablets or drink ]]>sport drinks]]> unless directed by your doctor.

Air conditioning
For those who do not like the blast of cold air generated by an air conditioner, Dr. Wetle recommends setting the unit to a more moderate temperature or cooling just one room for periodic respites from the simmering heat.

Other preventative measures:

  • Wear white, short-sleeve, loose-fitting, natural-fiber clothing.
  • Wear a wide-brim hat outside to provide shade.
  • Take a cool shower.
  • Cook with the microwave rather than the oven or stove.
  • If you do not have air conditioning, cover windows to block sunlight and visit an air-conditioned library or mall.
  • Do not go out during the hottest part of the day.
  • Pace your activities.
  • Ask a friend or relative to check on you twice daily.

The Dangers of Extreme Cold

Inactive older adults generate less body heat and can easily lose body temperature. "We get more publicity about people dying from hyperthermia. But I suspect some of the deaths that occur in the winter are hypothermia-related, but they are never recognized and, therefore, don't get counted that way," Dr. Wetle says. A hypothermic death can look like heart failure or an accident. "Older people can be in their own home at 60 degrees and run into trouble," Dr. Wetle warns.

In the house, keep the heat on, wear multiple layers and use extra blankets. And when going out, bundle up. Wear gloves, a hat and several layers. Stay indoors on cold, windy days. Winds hasten cooling.

A drop in core body temperature can kill. Symptoms include confusion; sleepiness; slow, slurred speech; a weak, slow pulse; extremity stiffness; and slow reactions. Shivering may or may not be present. Check your body temperature with a thermometer. If it's below 96 degrees, if it's unreadable or if in doubt, call for medical help.

To help someone with hypothermia until emergency medical help arrives, keep him or her warm with additional blankets or your own body; if he or she can swallow, offer warm liquids but no alcohol, which expands blood vessels near the surface and lets needed warmth escape. Do not rub the person's skin.

Raynaud's Phenomenon

Some older adults with rheumatic, nervous or circulatory conditions, such as arthritis or hardening of the arteries, suffer from Raynaud's Phenomenon. Smoking and some medications used to treat heart conditions or migraines can also cause this condition, which is unrelated to hypothermia.

When exposed to cold, small blood vessels in the hands and feet contract, blocking blood flow. The skin turns white, then blue, then red as circulation returns. The area feels numb or prickly. Doctors recommend that people with Raynaud's stay warm indoors and out, with socks, multiple layers of gloves and mittens, and scarves. Wear mittens when taking food from the refrigerator. Sufferers also must protect against injury to the skin and stop smoking.

Be Prepared for Temperature Changes

Aging makes regulating body temperature more challenging during hot and cold spells. Seasonal temperature changes and activities once taken for granted pose potential problems with declining reserves, chronic conditions and medications. Play it safe—wear seasonal clothing, modify established habits and create a buddy system to check on each other.