Summers Are Getting Hotter and Deadlier, Especially for Older Americans

The risk of heat rises with age

No region of the country is immune to a potential heat disaster. And the risk is accelerating. During a heat wave that struck Texas and Oklahoma in 2011, Dallas experienced 40 straight days of at least 100 degrees. The following year, a blistering spring in the upper Midwest drove the thermometer in Madison, Wisconsin, a full 40 degrees over the average — in March. Montpelier, Vermont, has broken daily June highs nine times in the past five years. Reno, Nevada, hit 106 only a single time from 1893 to 2000, but the city matched or exceeded that peak eight times in the 25 years since. And in March of this year, a massive heat dome broke records for the month in 14 states; in Arizona and California, thermometers hit 112 degrees.

Across the country, the consequences have been increasingly fatal. From 1999 to 2023, heat-related deaths in the United States jumped 117 percent, according to JAMA. While official statistics tallied about 2,300 heat deaths in 2023, that’s likely an undercount. A 2020 Duke University study suggested a more accurate heat-death total hovered around 12,000 annually. That’s because no national standard exists for determining what counts as a heat fatality. Many death certificates list causes of death that can be triggered by extreme temperatures, such as heart attacks, ischemic strokes, asthma attacks and renal failure, while the real culprit remains unstated.

The physiology is well understood. When temperatures skyrocket, the human body relies on an arsenal of responses to protect itself. Blood rushes to the skin to radiate the heat outward, and sweat evaporating off the skin helps cool the body. We crave water to replenish the fluid we’re losing. We yearn to slow down and find shade. And the hotter we get, the harder the cardiovascular system works to cool us down. The heart rate increases, and blood vessels open wider.

But over time, the body’s cooling systems become less effective. Older people feel less thirst, even when they’re dehydrated. They don’t sweat as much. As blood vessels stiffen, the heart has to work even harder to push blood to the skin’s surface. Hormonal and metabolic changes can blunt biological responses, as can blood pressure pills, diuretics and some antidepressants. Conditions such as asthma, diabetes and kidney disease can also impair the body’s ability to cope with high temperatures.

When an older person overheats, their blood pressure drops and core temperature rises. If they don’t find a way to cool down, what starts as heat exhaustion — with symptoms such as dizziness and nausea — can progress to heatstroke, an urgent condition that can cause irreversible organ damage or death.

Another symptom of heat exhaustion is faulty decision-making, which means the person may not even realize they’re in need of help. Kristie Ebi, a climate health professor at the University of Washington, told me about an older acquaintance who played tennis one hot day, came home and rehydrated while sorting his mail. After he showered, he found his bills in the trash and his trash in the freezer. His core temperature had risen to the point where he was disoriented without realizing it.

To stay safe from the heat, it’s important to acknowledge its danger. “To an older adult who’s like, ‘Oh, I’m going to go for a walk at noon today because I could do it 20 years ago,’ well, they have to recognize that both their body is changing and the climate is changing,” says Deborah Carr, a Boston University professor who studies heat and aging. “Temperatures are hotter, and you are older and less heat-tolerant.”

The uneven distribution of danger

Shandas and I drove beneath a freeway and toward the Portland suburbs. Off in the distance, the glaciated flanks of Mount Hood beckoned. On the hottest day of the heat wave, Shandas told me, he’d driven past properties where homeowners had left out icy coolers of drinks for passing strangers. Shandas, too, had pulled over several times that day so he could hand out water bottles at bus stops. Not one person turned him down. He found their apathy and exhaustion disconcerting. “There wasn’t anyone who said, ‘I’m good,’ ” he recalled. “Everybody was like, ‘Thank you. Thank you. Thank you.’ ”

Few people truly appreciate the power of heat, its capacity to sneak up without warning. As Jeff Goodell put it in his 2023 bestseller The Heat Will Kill You First: Life and Death on a Scorched Planet, “It doesn’t bend tree branches or blow hair across your face to let you know it’s arrived. The ground doesn’t shake. It just surrounds you and works on you in ways that you can’t anticipate or control.”

What’s more, heat doesn’t blanket a city at a uniform temperature. Areas with trees, grass and shrubs stay far cooler than those with lots of asphalt, which absorbs the sun’s rays and releases heat at night. The difference between the hottest and the coolest areas often correlates with money and influence. As Shandas discovered over years of research, temperatures within a relatively small area can vary by as much as 25 degrees — enough to mean the difference between life and death. You can be at greater risk than someone across town, across the street or even in a different unit within the same building.

This was evident as 2021’s tragedy unfolded. On the hottest day, Shandas took measurements in Portland’s Ladd’s Addition, a strip of big homes surrounded by green lawns shaded by century-old elms. The air was hot but survivable. But in the lower-income neighborhood of Lents, near several highways, a chain-link fence and an abandoned lot, Shandas touched his hand to the pavement and had to snatch it quickly away. “You couldn’t even keep it on there for a second,” he says. It was “like putting it on a flame.” That’s where his air temperature gauge showed 125; the surface temperature was 185.

One day during my visit to Portland, I motored down to a neatly tailored community for older people, south of the city. Spiffed-up mobile homes trimmed in yellows, blues and browns baked in the midday sun. Inside one of them I met Joanne Reed, 86, a tiny, friendly woman with a pouf of white hair. She sat on her couch and told me what the heat had stolen from her.

“If you want to turn around, there’s a picture right there, in the middle,” she said, gesturing toward a photo on the thin wall behind me. It was a picture of Reed dancing with a younger, mustachioed man. When I turned back, she looked down. She had just bathed her dog, Mitzi, and now stroked her pet’s wet ears. After a beat she looked up. “That’s Kent.”

In 2021, Reed lived in Tucson, Arizona, while her son Kent Christman, 63, lived here alone. When she heard Portland was about to get hot, she checked in. “I said, ‘Are you using the AC?’ And he said, ‘No,’ ” Reed recalled. She was immediately concerned. He told her he preferred fans and open windows to driving up his electric bill. “He said, ‘I’m managing OK,’ ” Reed said.

Reed feared he was not; he was always careful with his money. So each day, as the thermometer climbed, she got nervous and called again. She got no answer. “The first day, I thought, Well, he’s got a new phone, and it’s probably hard for him to use it, so I left a message.” Later, she thought he might have stepped out with friends.

By the third day, “I was panicking,” Reed said. When he didn’t respond again, she called the sheriff. They found Kent dead on the couch, in front of a fan. The coroner’s report listed the cause of death as hyperthermia. Kent simply hadn’t been able to lower his body temperature fast enough.

“People aren’t really good at preparing for things they haven’t seen before,” says Karen McKinnon, a climate scientist at the University of California, Los Angeles. “Behavioral adaptation takes time — and when you’ve never lived through something this hot, you’re often caught off guard.”

A hot and hazy future

It’s not just individuals who need to adapt, though. It’s governments, aid organizations, housing providers and more. And vulnerable populations, including older people, must be at the center of their attention.

The number of people over 60 worldwide is expected to double to 2.1 billion in the next quarter century. Meanwhile, retirees in the U.S. are still moving south. That combination increased the number of people over 65 living in some of our hottest places — Arizona, Georgia, South Carolina — by more than 50 percent between 2010 and 2020.

At the same time, colder areas, especially in New England and the upper Midwest, are heating up faster and more dramatically than the already hot Sun Belt. These places, too, have significant populations of older residents but frequently lack the infrastructure to tackle high temperatures. The number of air-conditioned homes in Maine, New Hampshire and Vermont is far below the national average. And Maine has proportionally more residents over 65 than any other state.

But even access to air-conditioning is no guarantee of safety. During Hurricane Irma in 2017, a dozen people, ages 57 to 99, died from exposure to excessive heat when the transformer powering the air-conditioning at their Florida nursing home blew. An older woman died in 2024 from heat-related causes in Arizona when the power company shut off her electricity for unpaid bills. At least seven of those who died in Portland in 2021 had air-conditioning units that either were unplugged or didn’t work. In some states, AARP offices have advocated for summer disconnection moratoriums to prevent utility shutoffs during dangerously hot weather; several states have since enacted related laws, but more than half still allow such shutoffs. Most states also lack requirements for backup generators at long-term care facilities, which would ensure that nursing homes or assisted living facilities wouldn’t lose air-conditioning if the power went out during a heat wave.

Experts confess to an even bigger fear. During peak demand, utility companies in hot cities often beg residents to dial back their electricity use to avoid blackouts. But energy demand — and costs — are climbing quickly, and the power grid is aging. “Air-conditioning is only as good as the electricity behind it, and in a heat wave, that’s the very thing most at risk,” Shandas told me. “If the power goes out during a heat wave, we are cooked — literally cooked. And it’s the older adults who will face the disproportionate burden of that outage.”

In fact, research in 2023 determined that such a tragic scenario over a period of five days in Phoenix could send half of the city’s 1.6 million residents to the ER. The projected number of deaths: about 13,000.

‘Truly a wake-up call’

When the heat receded from her apartment in 2021, Beth Parmenter, the nurse and volunteer, was still very much alive. Her dark sheets and honeycomb shades, fans and the other precautions she took may well have saved her life. But Parmenter knows she took a risk by staying put. What Portland went through “was truly a wake-up call,” she told me. “It scared me.” In 2024, she and others in her building got together and had air-conditioning installed.

Parmenter remains haunted by the voices of some of those she called as a heat-wave volunteer. She still recalls the helplessness she felt not knowing how — or whether — people would act on her call. She thinks often of one particular man, a lonely, frail-sounding gentleman. He hadn’t yet turned on his air conditioner because, he told her, “I can’t afford to. I won’t be able to eat.”

Due to the confidentiality of her volunteer role, she never found out how he fared, but to this day she feels the weight of what he said. The Pacific Northwest, with its abundant hydropower, has some of the cheapest electricity in the country, and he still had to worry about utility rates forcing him to skip meals.

Portland and other places in the Northwest have begun enacting heat-mitigation policies, planting trees and breaking up parking lots with shrubs. Construction design rules now mandate that apartments keep indoor temperatures at or below 78 degrees. Some local governments now even provide air-conditioning to low-income homes and have installed thermometers in some subsidized housing to better understand indoor temperature risks.

These adjustments make a lot of sense: Research suggests that by 2040, with continued warming, heat events could strike the Northwest roughly every five to 10 years.

To help other localities take action, Shandas has put together neighborhood temperature maps for more than 130 cities worldwide, many of which have now put in place heat-mitigation practices. Shandas encourages older people to reach out to local leaders to make sure they have a plan for extreme heat.

There is plenty that individuals can do to prepare themselves, Shandas adds. If you don’t have air conditioning, consider installing it and look into local subsidies. And don’t be a hero — if you don’t have a way to keep your home cool, make plans to stay somewhere else when excessive heat is in the forecast.

Surviving a heat wave involves more than just air conditioning, though. “Heat resilience is not just about cooling,” says Shandas. “It’s about hydration, preparation, social support and awareness.”