We're underestimating the way heat harms our health and kills us, ASU researcher says
Maricopa County identified 425 heat-associated deaths in 2022, but one local researcher says that number is likely a vast undercount.
Dr. Pope Moseley, a physician and research professor at Arizona State University's College of Health Solutions, has been researching heat-related illness for three decades and cites evidence that shows heat waves increase suicides, heart attacks, drug-overdose deaths and hospitalizations for dementia, among other things.
Heat, particularly when it's prolonged, can make people with underlying health conditions such as diabetes, asthma and heart disease more vulnerable to heat illness, to exacerbated health problems and to death, Moseley said. In other words, his research shows that heat-related deaths recorded in public data are likely only a fraction of the overall mortality from heat.
"Heat is a force multiplier for chronic disease," Moseley said Wednesday. "Heat makes it much worse. It's important because 65% of Americans have at least one chronic condition and 40% have more than one."
Such findings are not good news for Phoenix residents, who this month have been experiencing scorching, record-breaking temperatures without the relief of monsoon rain.
Maricopa County, where about 64% of the Arizona population lives, as of July 15 had recorded 18 confirmed heat-associated deaths in 2023 with 69 more under investigation. However, because of the multiple sources involved in reporting heat deaths and the investigation it takes for a death to go from suspected to confirmed, the county likely will not have a complete tally of deaths resulting from the ongoing 2023 heat wave for some time, county health officials say.
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Moseley and Marisa Domino, a professor in ASU's College of Health Solutions, are conducting research into heat illness using hospital and population data. The hope is to make the public aware that more people are impacted by heat than those suffering common heat-related illnesses such as heatstroke.
Ideally, the research will lead to a climate smartphone app, building on a previous model from the University of Copenhagen that predicted outcomes for critically ill patients, said Moseley, who was part of the Copenhagen research group. A climate app could allow individuals to input their own health data and then the app would be able to determine personal risk of being outside for an extended period of time, whether it's the risk of hospitalization or dying.
"Data from population studies in Sweden have shown that for every heat wave day, you have an 8% to 12% increase in overall mortality," Moseley recently told ASU News. "Our job in the College of Health Solutions is to put together the data to allow policymakers to plan and manage what’s going to happen during a heat wave."
Cold exposure causes more deaths than heat exposure worldwide, according to The Breakthrough Institute, a California-based environmental research center. But Moseley told The Arizona Republic that cold doesn't adversely impact medical conditions the way heat does.
"Heat acts across a number of diagnoses," he said. "Direct cold probably kills more people, but the exacerbation of illness is much worse for heat."
Socioeconomics play an obvious role in who is most vulnerable to heat, as someone with a chronic disease who is unsheltered, living in a home without air conditioning, or working in a job that requires outdoor labor in the summer heat, is going to be far more impacted by heat than a person who is spending most of their time in an air-conditioned home.
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But even that person living in air conditioning would benefit from knowing how the outdoor temperature is affecting their health, so they can gauge their vulnerability and risks when spending time outside, Moseley said. The data model that he is working on with Domino is intended to help calculate heat risk, where individuals or individuals in identified groups can know how vulnerable they are to health problems from specific lengths of time in the heat.
The model could be used for cities, and for health systems, too, he said, and it could be particularly helpful in helping to allocate health resources in the event of a power failure during a heat wave.
"Health systems could look at the patient population and get a pretty good idea of what was going to happen during a heat wave, who was going to show up — not just heat illness," Moseley said. "Is it going to be heart attacks? Is it going to be respiratory disease? Is it going to be people with heart attacks and respiratory disease? ... It could actually help the health system direct its resources."
Moseley said public awareness about the health dangers of heat is critical because the toll of heat waves doesn't always get the ongoing attention that it should. He cited as an example the European heat wave of 2003, which conservative estimates place as having a death toll of 70,000 people. By comparison, another weather-related disaster — Hurricane Katrina — had a death total of an estimated 1,392 people, according to the National Hurricane Center.
Phoenix is an ideal "ground zero" for studying extreme heat because the daily low temperature has been quickly increasing, partially because of rapid urbanization, Moseley said. While Death Valley is extremely hot, it cools overnight in a way that Phoenix increasingly does not because of all the concrete that holds onto heat, not unlike a brick oven, he said.
"If you go to Death Valley right now, the lows are probably going to be in the mid-80s. If you’re in Phoenix for the next 10 days, our low temperatures are going to be around 90. If you ask me, as an intensive care physician, which one scares me more, it’s Phoenix," Moseley told ASU News. "There is pretty good population data from the European heat waves in 2003 showing that it wasn’t the high temperatures, but how long it was hot. That means that the area never cooled, as we see in Phoenix right now."
Though his research on heat illness may sound grim for Arizonans, Moseley told the Republic he's impressed by the steps the city of Phoenix is taking to limit the heat risk for vulnerable populations. City officials and academic researchers are continuing to look at ways to cool down those daily low temperatures in Phoenix because it is possible to do that, he said.
"We can do some work with better materials, more shade, more green spaces," Moseley said. "The city of Phoenix is doing a very good job at trying to address this. ... Phoenix is already addressing issues that will face many, many cities in the next 20 years."
Reach health care reporter Stephanie Innes at Stephanie.Innes@gannett.com or at 602-444-8369. Follow her on Twitter @stephanieinnes.
This article originally appeared on Arizona Republic: Prolonged heat is a force multiplier of chronic illness, research says
