Bloomberg: Why older adults are feeling the heat more

Why older adults are feeling the heat more

By Zahra Hirji 

When a heat dome shattered temperature records across the Western US and Canada in June 2021, the resulting fatalities exposed a pattern. In Portland, Oregon, and surrounding Multnomah County, 56 of the 72 people who died were aged 60 and up. In British Columbia, people 60-plus accounted for 555 of the 619 fatalities. Just over a year later, a sizzling June, July and August in England caused roughly 2,800 excess deaths among people 65 and older. More than 1,000 of them occurred over four days in late July. 

Intense heat waves in recent years offer a stark warning of what’s at stake for humanity. The planet just endured its 12 hottest consecutive months on record, and this summer threatens to be hotter than ever. But those stakes are not experienced equally across age groups. Older adults are more at risk of experiencing dangerous health impacts during periods of intense heat.

“Older adults are one of the populations that we classically see as being more vulnerable to the effects of climate change, specifically to effects of extreme heat,” says Catharina Giudice, an emergency physician and climate change and human health fellow at Harvard’s FXB Center. “As we age, our ability to adapt to heat diminishes.”

 

Tourists cool off by a water spraying fan in Rome during a heat wave in July 2023.  Photographer: Tiziana Fabi/AFP/Getty Images

When confronted with rising temperatures, the human body has two main tools for thermoregulating, or avoiding overheating. The first is sweat, which releases heat when it evaporates. Compared to young and middle-aged people, “older people don’t sweat as much,” says Deborah Carr, a professor of sociology at Boston University who studies aging. “They have essentially a less efficient cooling system. So they’re in extreme heat and don’t sweat it out.”

The second tool is increased circulation of blood, which draws heat from deep inside the body to the skin, where it can escape. “The heart has to sometimes pump two to four times more blood each minute than it would on a cooler day,” says Renee Salas, who is affiliated with the Center for Climate, Health, and the Global Environment at Harvard’s T.H. Chan School of Public Health.

A healthy heart can handle all that extra pumping, but people suffering from heart disease and other cardiovascular issues may struggle. Older people are more likely to have those conditions, as well as other chronic issues like diabetes, hypertension, and lung problems, all of which can inhibit the body’s ability to respond to heat. Many of the medications used to treat those and other health conditions also impair that response, such as by decreasing the ability to sweat or increasing urination that can trigger dehydration. 

 

Elderly residents sit in the shade a heat wave in Ourense, Spain on Aug. 8, 2023. Photographer: Brais Lorenzo Couto/Bloomberg

Meanwhile, the planet is continuing to warm. Global average temperatures are already 1.2C above pre-industrial levels, and heat waves are more frequent and more intense than they were just a few decades ago. At the same time, the elderly’s share of its population is also increasing. In 2021, there were roughly 1.1 billion people 60 years or older globally; by 2050, that’s projected to hit nearly 2.1 billion people. In the coming decades, far more older adults will be exposed to dangerous levels of heat than are today. 

“People are living longer because of better access to health care, better access to nutrition,” says Giacomo Falchetta, a climate researcher at the Italian research institution CMCC and lead author on a study of heat exposure for older adults that was published in Nature Communications in May. But “climate change is increasing the frequency and intensity of heat exposure.” 

The study, which Carr at Boston University co-authored, projects that by 2050 roughly 24% of the global population at least 69 years old will be living in places where maximum temperatures exceed 37.5C (99.5F). At that point, between 177 million and 246 million more older adults will be exposed to dangerous heat than are now.

Falchetta frames those conclusions as actionable: He hopes the research will inform city and country officials about heat’s growing threat so they can plan to better protect their older citizens.

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