Both extreme cold and hot weather kill older adults. The US Centres for Disease Prevention and Control report that between 2006 and 2010 deaths from cold weather for older adults (aged 65 and older) were three times those caused by heat. Cold weather kills more older adults.
Although younger people die from both extreme heat and cold temperatures, they are usually caught outside without protection. For older adults, extreme temperature kills them in their home. Older adults, aged 85 and older, are 13 times more likely to die of the cold than younger adults, while when it comes to heat-related deaths, they are eight times more likely to die. Understanding why this happens is intriguing.
Older adults are less capable to deal with such changes because of existing ill-health. The older we become, the more likely we are to accumulate health problems. These health issues reduce our ability to deal with heat and cold. To make matters worse, some medications we take for heart problems, blood pressure and other type of drugs, such as sedatives and tranquillisers, all reduce our ability to control body temperature.
The biggest issue, however, is radical. As we get older, signals between the body and brain become more muted so that temperature awareness is muffled. We are less aware that it is too hot or too cold. Also, the ability to control body temperature depends of having adequate food (salt) and water.
Older adults tend not to feel thirsty as quickly as younger people. It is likely that older adults are more likely to already be dehydrated. The solution might be simple – to drink regularly – but we do not follow this because we hate going to the bathroom all the time. But there is another impediment for older adults. Our body is trying to save energy.
Surprisingly, older adults do have slightly lower temperatures. The 98.6°F benchmark for body temperature does not apply to older people. This “normal temperature” comes from Carl Wunderlich – a 19th-century German physician. More recent data in 2005, by Irving Gomolin from Winthrop University Hospital in New York, found that older people have lower temperatures than younger adults.
The reason older adults have lower body temperature is not because they are dying, but because it is nature’s strategy for keeping them alive longer
In a study of older people aged 80 and older, it was found that the average temperature was 97.7°F. What is fascinating is that the older you get, the lower your body temperature becomes.
Although most scientists see lower temperature as correlated with death, an indication that the body is shutting down, there is an alternate explanation. Lower body temperature might be a protective function, an indication that the body is conserving energy and reducing metabolism to help you survive longer. And that is exactly what a 2006 research study found.
Bruno Conti, an Italian researcher with the Scripps Research Institute in San Diego, showed that a decline in body temperature is beneficial. Using mice as his study group, Conti found that mice that had lower core body temperatures lived 12 per cent (male) to 20 per cent (female) longer than mice with higher core body temperatures.
The difference in temperatures between ‘cold’ and ‘normal’ mice was 0.5 to 0.9°F, which is the same difference between the average human adult and older adults. Perhaps the body is conserving energy by reducing its operating temperature and therefore reducing metabolic rate, free radicals and reducing stress on the system.
The science behind this anomaly is just now becoming clear to us. One of the known ways to increase longevity is to restrict how much we eat, especially from calories. Caloric restriction increases life span and health in all sorts of animals; it also reduces body temperature. It could be that lowering body temperature is one way that the body uses of slowing the ageing process.
Thus, the reason older adults have lower body temperature is not because they are dying, but because it is nature’s strategy for keeping them alive longer.
In the Baltimore Longitudinal Study of Ageing, men with a core body temperature below the average lived significantly longer than men with body temperature above the average. This might be a perfect strategy, except when the outside temperature drops, the reduced body temperature proves to be a hindrance. A lower body temperature means we have less flexibility in controlling it.
But the biggest problem is isolation.
In 2003, during a major European heat wave, 14,802 people died of hyperthermia in France alone. Most were elderly people living alone in apartment buildings without air conditioning. Every year there is a European summer exodus, where city residents head to the countryside leaving their elderly relatives behind. If such deaths occurred among children, there would be political repercussions. But we have less regard for older people. We need to educate ourselves better: ‘Forewarned is forearmed’.
Protect yourself when extreme weather is forecasted; no one else will.
Mario Garrett was born in Malta and is currently a professor of gerontology at San Diego State University in California, US.