All over the country, we are recording the hottest summer in many decades. Seniors especially need to be aware of the dangers of these record-high temperatures. Now, in addition to heat stroke and other heat-related health issues, new research indicates that this extreme heat could lead to an earlier onset of dementia!
The research suggests that long-term exposure to extreme temperatures may be literally frying brain cells!
The study of nearly 9,500 older U.S. adults found that those with greater exposure to heat waves over 12 years also showed a steeper decline in cognitive function — critical mental skills like memory, reasoning, and judgment.
The connection was specifically seen among older Black Americans and those living in poorer neighborhoods — groups who typically have fewer resources to protect themselves from scorching summer heat.
Cognitive decline is complex and influenced by many factors, said lead researcher Eunyoung Choi, a postdoctoral associate at NYU School of Global Public Health in New York City.
“Isolating the specific effect of extreme heat from this complex web is a challenging task,” she said.
At the same time, there are reasons that repeated exposure to heat waves could affect older adults’ mental acuity, according to Choi.
For one, there could be direct effects: Extreme heat can dull mental performance in the short term, and continued exposure over time might promote inflammation and damage to brain cells.
Sizzling temperatures could also act in indirect ways, Choi said. She pointed to the well-known link between heart health and brain health.
Certain cardiovascular and metabolic conditions, including high blood pressure, diabetes, and heart disease, are tied to a heightened risk of cognitive impairment — possibly because they impede blood flow to the brain. Extreme heat might make those conditions worse.
Beyond that, Choi said, oppressive heat makes it hard to sleep or leave the house for exercise or social activities — all of which can take a toll on older adults’ cognition.
Why would low-income and Black Americans be more affected? Choi said there might be a role for “cognitive reserve” — the brain’s capacity to adapt and preserve function even as age or disease starts to change the brain tissue itself.
People who are disadvantaged — facing chronic stress and fewer educational and work opportunities, for example — may start off at a lower cognitive reserve and see it erode faster over time, Choi said.
And that, she added, may make them more vulnerable to any added stressors, like extreme heat.
All of those scenarios are plausible, agreed Kristina Dahl, principal climate scientist with the nonprofit Union of Concerned Scientists.
“I think this study is very interesting,” said Dahl, who was not involved in the research.
She said scientists know something about the acute effects of extreme heat on cognition. And many people, she noted, have experienced “that sluggish feeling in the brain” that can come with summer heat waves.
The new study, Dahl said, begins to connect cumulative heat exposure to longer-term cognitive decline.
While there are plenty of questions for future studies, Dahl said now is the time to protect vulnerable Americans from extreme heat.
That, she said, can include ensuring that people in low-income areas have easy access to cooling centers, barring utilities from shutting off people’s electricity due to unpaid bills, and making sure outdoor workers have enough shade, water, and rest.
