Why extreme heat brings worse mental health — and what you can do about it.

A heat wave brings familiar collective grumbling. We make jokes about ice baths, grouse about sleepless nights, and trade tips about creative ways to cool down.

But with research suggesting that this summer's grueling global heat waves are linked to climate change, we can likely expect seasonal griping to become our new normal. It's a frightening prospect, particularly because the silent struggles we face tell a more complicated story about how humans, and their mental health, fare when subjected to extremely hot temperatures.

Last year, a study published in JAMA Psychiatry demonstrated how higher temperatures are associated with a noticeable uptick in emergency department visits for mental health treatment. Previous studies on the subject have yielded similar results. A recent Lancet Planetary Health meta-analysis of studies on rising temperatures and mental health also identified potential links when researchers looked at heat and suicide, hospital admissions for mental illness, and worsened community health and well-being.

There's something about heat waves that lead to worse mental health, whether that's judged by self-reported measures or medical records like hospital visits.

Research on the subject bolsters the case that extreme heat related to climate change takes a toll not just on the body, but also the spirit and mind. While this might be of particular concern for vulnerable populations with limited access to resources including cool shelter, like farm workers or the unhoused, the association also holds true for people who have access to private insurance and Medicare, according to the JAMA Psychiatry study.

Using data collected over a 10-year period from more than 2 million patients, the researchers found that days with extreme heat were associated with increased emergency department visits for mental health conditions like substance misuse, anxiety, schizophrenia, and self-harm. That span of time represents several of the warmest years on record in the United States.

A 2022 report published by the Intergovernmental Panel on Climate Change included a lengthy discussion of the connection between extreme temperatures and reduced well-being and mental health. That research found that increased heat is associated with suicide, psychiatric hospital visits and ER visits, and heightened anxiety, depression, and stress. Studies have also linked higher summer temperatures to decreased happiness.

Humans want to be resilient in the face of adversity, so they crack jokes about heat exhaustion or jury-rig a swamp cooler in their bedroom. They might wave away mounting anxiety as overreaction or pour another glass of wine to dull the edge of making it through another triple-digit day without air conditioning.

But the scientific research should be a wake-up call to anyone who thinks extreme heat is bearable with the right attitude. Coping skills are always valuable, but what we ultimately need are more adaptive and resilient systems that help shield everyone from the physical, emotional, and psychological toll of extreme heat.

How heat waves affect mental health

While the authors of the JAMA Psychiatry study couldn't conclude how extreme temperatures worsen mental health, they suggested sensible explanations: disrupted sleep, daytime discomfort or irritation, and an "increase in hopelessness, maladaptive anxiety, and stress attributable to the anticipation of climate change and associated extreme events."

Anyone who's waited for their home to cool off without the assistance of air conditioning during an extended heat wave knows the desperation can lead to anxious questioning about the future: How will my children survive a warming planet? Should I even have children if this is the world they'll inherit?

The researchers also speculated that an emergency department could be a refuge on a scorching summer day; the price of admission is to see a doctor about a mental health condition that needs treatment anyway. If patients are indeed using the ER to escape the heat, it represents the crux of this momentous problem.

Turning to the ER is a resourceful, if expensive, strategy, but improving our collective health will require preventive, equitable solutions. This could include more cooling centers and transportation to reach them, as well as initiatives to reduce the absorption of heat by man-made materials like cement, asphalt, and brick in urban areas through measures like increased tree canopies and green roofs, so that people can remain comfortable in heightened temperatures.

Ways to cope during a heat wave

In a co-authored editorial that accompanied the JAMA Psychiatry study, data scientist Dr. Nick Obradovich, who was not involved in the study, argued that it's vital to understand how extreme heat affects mental health so that public policies can precisely target ways to help people.

Months after the JAMA Psychiatry study appeared, Obradovich published a study that took sleep measurements from smartwatch data across 68 countries and linked it to local daily meteorological data. He and his co-authors found that higher temperatures seemed to shorten sleep by delaying its onset, which increased the chances of insufficient sleep. The results built on Obradovich's previous research on the topic; a 2017 study he co-authored helped identify the relationship between climate change and disrupted sleep.

If the main factor is that people sleep less when temperatures rise, and therefore experience worse mental health, then scientists and legislators could evaluate how best to improve the quality of a good night's rest on a hot day. In the future, that could potentially lead to the widespread adoption of architectural practices like passive cooling or building codes that encourage energy efficiency, which reflect the importance of cool nighttime temperatures.

Obradovich said there is still a critical need for better quality studies to improve our understanding of the relationship between rising temperatures and poorer well-being. He also suggested that by looking exclusively at mental health diagnoses available in medical records, we may miss emotional and psychological turmoil that hasn't risen — or won't rise — to the clinical level.

Imagine, for example, the stressed single parent trying to stay patient with a screaming toddler in an overheated house during a summer of heat waves. Or a lonesome senior who feels trapped and scared in the midst of record-high temperatures. Even if these experiences don't lead to an official diagnosis, they influence people's well-being. Writ large, temperature spikes can send a shockwave of angst through households and communities.

"When you sum total the effect of a million people being a bit more grumpy than they otherwise would on any given day, that's something worth paying attention to as well," Obradovich, chief scientist for environmental mental health at the Laureate Institute for Brain Research, told Mashable.

People with resources may seek therapy to help process their feelings, or turn to other practices like mindfulness and meditation. They may resort to what Obradovich calls private adaptations: installing air conditioning, moving to a region less affected by extreme heat, or simply skipping town when a heat dome arrives.

Obradovich says there's no sense in feeling shame, or shaming others, for making these choices. It's vital that people stay cool, but we must also pursue adaptations that benefit everyone while minimizing carbon emissions and ultimately moving away from energy systems that rely on carbon-emitting fossil fuels.

This is partly an individual responsibility, as much as people can influence politics and the marketplace through their pocketbook, activism, and ballot. Beyond that, this problem is one that will require leadership from elected officials to solve. Their duty to protect and serve constituents not only includes continuing to prevent heat-related deaths, but also acknowledging, and providing resources for, the mental health toll of extreme temperatures.

Whether that's through free or subsidized therapy sessions with climate-aware psychologists, or funding for community-led mental health interventions like support groups, or sponsoring fresh ideas that spring from the inventiveness of their constituents, it's time to imagine alternatives to pretending we're all going to be fine. The problem is at our doorsteps now, and will only continue knocking louder.

UPDATE: Jul. 26, 2023, 12:32 p.m. EDT Originally published in February 2022, this story was updated in July 2023.

UPDATE: Feb. 28, 2022, 1:34 p.m. EST This story has been updated to include findings from the IPCC Sixth Assessment Report on Impacts, Adaptation and Vulnerability.