When a heat dome shattered temperature records in 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 60 and older. In British Columbia, people aged 60 or older accounted for 555 of the 619 fatalities.
Just over a year later, a sweltering June, July and August in England caused around 2,800 extra deaths among people aged 65 and over. More than 1,000 of them took place over four days in late July.
The intense heat waves of recent years provide a stark warning of what is at stake for humanity. The planet has just endured its 12 hottest months in a row, and this summer is shaping up to be hotter than ever. But these interests are not experienced equally in all age groups. Older adults are at greater risk for dangerous health effects during periods of intense heat.
“Older adults are one of the populations we have traditionally viewed as more vulnerable to the impacts of climate change, particularly the impacts of extreme heat,” said Catharina Giudice, an emergency physician and climate change and human health fellow at the FXB Center from Harvard. “As we age, our ability to adapt to heat decreases.”
When faced with rising temperatures, the human body has two important tools to regulate temperature or prevent 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 essentially have a less efficient cooling system. So they’re in extreme heat and they’re not sweating it out.
The second aid is increased blood circulation, which draws heat from deep within the body to the skin, where it can escape.
“The heart sometimes has to pump two to four times more blood per minute than on a cooler day,” says Renee Salas, an associate professor at the Center for Climate, Health, and the Global Environment at Harvard’s TH Chan School of Public. Health.
A healthy heart can handle all that extra pumping, but people suffering from heart disease and other cardiovascular problems may struggle. Older people are more likely to have these conditions, as well as other chronic problems such as diabetes, high blood pressure and lung problems, all of which can hinder the body’s ability to respond to heat. Many of the medications used to treat these and other health problems also hinder that response, for example by reducing the ability to sweat or by increasing urination, which can cause dehydration.
“Medications can ironically increase some of those heat effects,” says Giudice.
The warning signs of dangerous heat can also be more difficult for older adults to identify themselves. That’s because older adults generally don’t perceive heat in the same way, says Glen Kenny, a professor of physiology at the University of Ottawa who studies how heat affects the body.
If a young or middle-aged person were to sit in the heat, Kenny says, he or she might have a hard time enduring it, while an older person in the same heat “might say, ‘I’m fine.'” The cause of This gap The number of reported heat symptoms remains unclear, but research by Kenny and his team shows that it can be dangerous: by the time an older person experiences acute discomfort due to high temperatures, their body can already be suffering significantly.
And those are just the physiological disadvantages. Many older adults also live alone and are socially isolated, making them less likely to have a support network. In British Columbia in 2021, for example, Kenny says many of the elderly who lost their lives were “living alone” and “had no support or family members” to keep an eye on them as the heat wave continued.
All of these risks exist today: Earth’s average temperature is already 1.2 degrees Celsius above pre-industrial levels, and heat waves are more frequent and intense than just a few decades ago. This year alone, excessive heat has closed schools, pushed power grids to their limits and claimed lives around the world. But as the planet continues to warm, the share of elderly people in the population is also increasing. In 2021, there were roughly 1.1 billion people aged 60 or older worldwide; by 2050 this is expected to affect almost 2.1 billion people. In the coming decades, many more elderly people will be exposed to dangerous heat levels than are currently the case.
“There is a general trend in improving life expectancy,” said Giacomo Falchetta, a climate researcher at the Italian research institute CMCC and lead author of a study on heat exposure in older adults published in Nature Communications in May. live longer thanks to better access to healthcare and better access to nutrition,” says Falchetta. But “climate change increases the frequency and intensity of heat exposure.”
The study, co-authored by Carr of Boston University, shows that by 2050, roughly 24% of the world’s population aged at least 69 will live in places where the maximum temperature is higher than 37.5 C. At that time Between 177 million and 246 million more older adults will be exposed to dangerous heat than now.
Falchetta takes these conclusions as actionable: He hopes the study will inform city and rural officials about the growing threat of the heat so they can make plans to better protect their elderly citizens.
Some already are. Cities from Miami to Melbourne are expanding access to air-conditioned public places known as cooling centers, while also adding more shade and planting more trees.
In Athens, officials formally identified people over the age of 60 as among those most affected by rising heat. Social workers there check on the elderly and offer them transportation to cooling centers, said Elissavet Bargianni, Athens’ chief heat officer and head of the city’s Resilience and Sustainability Department.
In Canada, researchers and government officials from the University of Ottawa have collaborated on a health check guide, due out in 2022, aimed at helping people identify those for whom heat is particularly risky. The guide, which includes pointers on how to assess a person’s health status and keep them cool, also provides details on what to ask a loved one from afar, such as the temperature of their home and how they slept.
“Many sensitive people may not recognize when they are overheating, but another person can help identify a high-risk situation with some careful questions and observations,” says Sarah Henderson, scientific director of Environmental Health Services at the BC Center for Disease Control and the National Collaborating Center for Environmental Health, said in a statement when the guide was released: “Check in as often as possible. At least twice a day and once in the evening when it is hottest indoors.”
