Taking the heat as we age

Jul 8, 2017

Whether you love hot weather or can’t stand the heat of summertime, if you’re young and healthy, your body has a pretty efficient system for cooling itself down. But the body’s natural system for keeping a steady core temperature becomes less efficient as we age. That’s why older adults are at risk for heat-related illness like heat stroke and heat exhaustion.

This week on “Take Care,” Dr. Basil Eldadah of the National Institution on Aging discusses why older adults are more likely to experience heat stress. Eldadah is supervisory medical officer of the Division of Geriatrics and Clinical Gerontology at the NIA.

First, there’s no magic age at which heat starts to take a higher toll on a person. Eldadah says it has to do with overall health and the aging of the body, in addition to actual chronological age.

Eldadah says our bodies have a remarkable way of keeping our core body temperature in a pretty narrow range, despite large fluctuations in the ambient temperature of our environment.

The human body does this in two primary ways, says Eldadah.

First, sweat. When we sweat, the water on our skin evaporates and that leads to a cooling of the body.

Second, we have an intricate network of blood vessels in the skin that can dilate and constrict and help cool the body.

“Sort of like the way in which a car radiator works to bring fluid close to the air, which can then cool down the system,” Eldadah said.

So with older age, both of those mechanisms tend to reduce in function. Older adults tend to sweat less and that blood vessel system doesn’t work quite as well as it did at a younger age.

In addition to those two methods of self-cooling, there are other conditions that can predispose older adults to problems with heat regulation. One or more health conditions, like heart disease or diabetes, may interfere with the body’s ability to cool itself. And medications that individuals take for those conditions also interfere with the body’s cooling system – either with the ability to pump blood through those blood vessels, or with the body’s ability to maintain proper hydration.

Also, if an older person has limited physical or cognitive functions, that may reduce their ability to get out of the heat into a cooler place or hydrate, said Eldadah. And he said social barriers can play a role, too – like living alone or living on a fixed income, which can reduce access to air conditioning.

Heat-related illnesses, or hyperthermia, can come in many different forms and have many different names. The different terms are generally based on the symptoms, says Eldadah.

Heat exhaustion is called that because of the fatigue a person might feel in heat-related illness.

Heat stroke is a more severe form, which presents with a variety of conditions -- alterations in ability to think and central-nervous related symptoms that reflect a true medical emergency.

The earlier signs of heat-related illness include general feelings of weakness or light headedness. Eldadah says a person may have profuse sweating, pale skin, rapid breathing, fast pulse, headaches, nausea, vomiting, and their mental status may or may not be affected.

If heat stress progresses to a more severe form, you will see an elevated body temperature. Heat stroke is typically defined as a core temperature more than 104 degrees Fahrenheit, accompanied by other symptoms. Eldadah says, paradoxically, you may see hot dry skin rather than sweaty skin. A person may experience confusion, irritability, agitation or slurred speech, unsteadiness, alteration of consciousness, seizures, or a rapid or weak pulse. All of those things are indicators of a more serious condition that requires immediate medical attention, Eldadah said.

“Prevention is of course the most important thing to do, to avoid getting in that situation in the first place,” said Eldadah.

His recommendations for how to avoid heat-related illness include:

  • wear light colored, loose-fitting clothing
  • wear a hat to protect against sun
  • maintain hydration
  • avoid being outside during the hottest part of the day

If a person has one or more heat-related illness symptoms, Eldadah says there several things you can do to help reverse the situation. First, get out of the heat. Get to a cooler, shaded place or somewhere with air conditioning. Then remove excess clothing. Next, cool down with whatever means available, such as:

  • wet towels or ice packs on the head, neck, armpits and groin. This helps cool those blood vessels that are close to skin.
  • spray, mist or sponge down with cool water
  • get in front of a fan
  • take a cool shower or bath
  • hydrate, drink water

Eldadah says if you suspect heat stroke, call 911 and then start in on the list above.