Last year, many around the world were shocked and saddened when thousands of elderly men and women in France died as a result of a heat wave in that country. Here at home, the 1995 Chicago heat wave led to more than 700 deaths in that steamy city.

Heat-related illness can be a very serious problem, especially among older men and women. Health concerns – or just the normal physiological changes of aging – may make it difficult for older people to handle high temperatures.

Mark Supiano, M.D., a researcher and professor of internal medicine/geriatrics at the University of Michigan Health System, warns that summer heat can be dangerous and offers some tips to keep older people safe this summer.

"Heat-related illnesses and their problems begin to develop when the temperature exceeds 90 degrees Fahrenheit for more than two or three days," Supiano says. "When this is coupled with very high humidity, the risks to older people are even worse."

Older people who are at risk for heat-related illness include those who:

• Have impaired mobility, especially those confined to bed or those lacking transportation to leave their home for a cooler destination;
• Take medications that can impair temperature regulation, such as those with anticholinergic effects (e.g., Donnatal, and Benadryl), Thorazine, and Parkinson's disease medications;
• Take diuretics or other medications that lead to fluid loss, which can compound the problems of dehydration;
• Have a chronic disease, such as congestive heart failure or diabetes;
• Live alone, have poor social support or a poor social network;
• Lack access to air conditioning.

"Even healthy older people are at risk of developing heat-related problems, just because of the aging changes in their physiology," Supiano cautions.

There are a number of physiologic reasons why older people are at particular risk of complications from high heat and humidity. First, older people's ability to sense heat is impaired. And second, although younger people are able to discharge excess body heat, this ability is impaired in older people.

Supiano says that poor circulation is one barrier to adequately discharging excess body heat. Sweating is the other major method we use to discharge heat and this ability, too, can be impaired in older people.

"When outside temperatures are such that we cannot lose heat as efficiently as we otherwise would, we're at risk of increasing the internal body temperature. As heat builds up in the body, the early warning sign is heat exhaustion. If unrecognized and untreated, this can lead progressively to heat stroke, hyperthermia, coma and death," Supiano says.

There are a number of factors that are critical to preventing heat-related problems in older people. The first is education, including being aware of the potential problems than can contribute to heat-related illness. Once awareness is there:
• Make every effort to stay cool.
• Do what you can to get out of a hot environment.
• Stay in the shade.
• Limit outdoor activities.
• Use fans or seek areas that are air-conditioned, even if only for a few hours at a time.
• If possible, take a cool bath.
• Wear loose fitting clothing in lighter colors.
• Drink plenty of fluids and consume adequate nutrition.
• Avoid alcohol.
• Increase salt and electrolytes intake, such as through eating salty foods or drinking sports drinks like Gatorade.

Supiano points out that many older people are alone and vulnerable, requiring a community response to these preventable heat-related illnesses.

"Make certain your older neighbors are being cared for, including access to adequate fluids and food. If they don't have air conditioning, offer to take them to a place that has a cool environment, such as a shopping mall or senior center," he says.

For more information:

U-M Health Topics A-Z: Heatstroke
www.med.umich.edu/1libr/aha/aha_heatstro_crs.htm

MedlinePlus: Heat Illness
www.nlm.nih.gov/medlineplus/heatillness.html

CDC: Tips for Preventing Heat-Related Illness
www.bt.cdc.gov/disasters/extremeheat/heattips.asp

National Institute on Aging: Hyperthermia – Too Hot for Your Health
www.niapublications.org/engagepages/hyperther.asp