Hydrate, Hydrate, Hydrate!

"The elderly have been in lockdown for weeks. Our work is showing that the elderly are very vulnerable. They're isolated and many can't speak for themselves."
"As we age, there is a deterioration in the ability to lose heat."
"Canadians do adapt over the summer period, but it takes time."
"If any older person says they're hot then their core temperature is high. By the time they complain, it may be too late."
"A heat wave is a kind of trauma to the human body. The system takes weeks to adapt."
Dr.Glen Kenney, physiologist, University of Ottawa

Many elderly people don't rehydrate as often as they should and may also be on dehydrating medications, which could contribute to their higher risk of serious illness or death during heat waves. (Eric Gaillard/Reuters)

Growing older means a change of basic human physiology. Older people can no longer dissipate heat the way their young body enabled them to do. When young, core temperatures exposed to external heat such as through a prolonged heat wave, stabilize over time. The ability of the human body to adjust in this manner erodes as the person ages. Elderly people become warmer throughout a day-long exposure to high temperatures and they remain warm, the ability to dissipate internal heat impaired by age.

Dr.Kenny is a researcher with a specialty in studying how the human body regulates heat. He leads projects at the University of Ottawa with the use of the world's sole direct calorimeter, a device to make precise measurements of body heat exchange. In addition to age-conferred impairment in dissipating built-up body heat, the elderly burdened with chronic conditions like type 2 diabetes and high blood pressure, become even more vulnerable.

Where young people sweat to dissipate heat, older people tend to lose the ability to sweat. A study that measured heat dissipation in men between 20 and 70 discovered whole-body sweat rate to be significantly reduced in those between the ages of 45 and 70. Moreover, more heat was discovered by the researchers to be stored in men as young as 40 in comparison to younger men.

There is a sound, practical reason for older people to be cautioned not to exercise when the ambient temperature is too hot, even while the same precaution should be taken by those in their middle years. Both middle-aged and elderly people are vulnerable to heat-related illness during deadly heat waves. Seniors whose core body temperatures are high are seen to have increased heart rates resulting in an increase of cardiovascular deaths occurring during extreme heat events.

In July of 2018 over 90 people were held to have perished resulting from a heat wave in Quebec that year. Roughly three-quarters of the victims struggled with chronic illnesses; two thirds of them were over the age of 65. In geographic areas where temperatures change radically in a short period of time, it leaves no opportunity for the body to prepare for an oncoming heat wave, explains Dr.Kenny.

An example of how complex this situation can be and how it impacts on the health and longevity of the elderly is a law that mandates that Long Term Care homes have some air conditioned common rooms, but the requirement for bedrooms to have air conditioning is lacking. In areas where temperatures veer from cool to hot people have no opportunity to become acclimatized to the heat -- unlike those who live in climates which expose them for long periods of extreme heat.

Some of Dr.Kenny's research subjects have been elite athletes, first-responders, miners working underground, people with chronic disease and burn patients, some of whom may experience a sense of malaise or confusion during heat waves which can place them at risk of accidents and errors in judgement. As for the elderly, frequently they also tend not to show symptoms of heat stress.

Dr.Kenny's advice is to pay attention to hydration. And while cooling showers may be a good measure to reduce body heat built up during extreme prolonged heat events, this is not an option recommended for the elderly for whom wet towels placed around the neck and under armpits where blood vessels are close to the surface, is recommended.

Experts at the National Institute on Aging, part of the National Institutes of Health, say knowing which health-related factors may increase risk of heat exhaustion could save a life. Those factors include:

• Age-related changes to the skin such as poor blood circulation and inefficient sweat glands
• Heart, lung, and kidney diseases, as well as any illness that causes general weakness or fever
• High blood pressure or other conditions that require changes in diet, such as salt-restricted diets
• Reduced sweating, caused by medications such as diuretics, sedatives, tranquilizers, and certain heart and blood pressure drugs
• Taking several drugs for various conditions (It is important, however, to continue to take prescribed medication and discuss possible problems with a physician.)
• Being substantially overweight or underweight  
• Drinking alcoholic beverages
• Being dehydrated