Alaskans’ health starts suffering when temperatures climb to 70 degrees, and local and state officials should consider policies to respond to heat-related health problems that are expected to increase as the climate continues to warm, according to new research.
The results come from research led by Micah Hahn, an environmental epidemiologist at the University of Alaska Anchorage, that examined hospital visits in Anchorage, Fairbanks and the Matanuska-Susitna Borough and measured them against weather conditions from 2015 to the record-hot Alaska summer of 2019.
Hahn and her research partners found a direct tie between the heat index, a commonly used measure of heat and humidity, to heat illnesses, respiratory problems like asthma and cardiovascular problems, including heart attacks — starting at what might seem in the Lower 48 to be a mild temperature.
“At 70 degrees, we’re seeing health effects,” said Hahn, an assistant professor at UAA’s Institute for Circumpolar Health Studies.
Some of those effects took a few days to show up. Asthma, for example, generally set in the day after a temperature spike, she said. Other problems emerged as much as five days later, the team found.
Prolonged summer heat compounded the health risks, they found. For each day with a heat index above 72 degrees, the results showed that the odds for emergency department visits in subsequent days for heat-related illnesses increased by 9%, odds for visits for ischemia, the restriction of blood flow that causes a drop in oxygen supply to parts of the body, increased by 8%, and odds for visits for myocardial infarction, the technical term for heart attacks, increased by 12%. There were different risks for various demographic groups, with Alaska Natives more likely to be treated for ischemia, for example, and people over 65 more prone to heart attacks, the research found.
The study, which is to be published soon, can be used to help the National Weather Service and state and local health officials come up with a threshold for a tool that has not been used in Alaska in the past but might become important in the future, Hahn said: heat alerts.
“The whole point of this study was to try to figure out what’s the threshold where we should issue heat alerts,” she said.
In more southern latitudes of the country, the National Weather Service routinely issues heat alerts for high temperatures, such as 100 degrees or more. Clearly, that threshold would have to be lower in Alaska.
Part of the reason is acclimatization. Alaskans are simply not used to high temperatures, just as people in more southern latitudes are not used to cold temperatures.
That is a common phenomenon, said Brian Brettschneider, a climatologist with the National Weather Service. “No matter where you are, if it’s 10 degrees warmer than it should be for that day, it feels really warm,” he said.
But there is more that makes Alaska’s summer heat more intense.
The angle of the sun at Alaska’s high latitude — lower in the sky and present nearly around the clock — is a big factor, Brettschneider said.
“The sun angle’s lower, so the sun is physically shining on more of your body,” he said. That is different from a place like Texas or Oklahoma, where the sun is straight overhead, shines down and can be blocked by a hat.
Even his parents visiting from Texas have noticed that 70 or 72 degrees in Alaska seems extremely warm, he said. “It just feels a lot warmer than what the temperature reads,” he said.
At lower latitudes, the sun also disappears at night, allowing for cool evenings, Hahn added. “In Alaska, we really don’t get that respite,” she said.
There may be not much respite indoors, either.
“Homes in Alaska don’t have central air conditioning,” Brettschneider said. “All our homes are built to store every molecule of heat. They’re not made to promote airflow and stay cool.”
The angle of the sun in summer also affects indoor spaces, too, with light from the low-hanging sun streaming directly through windows for long periods, heating up floors and carpets, he said.
On top of that, there are lifestyle factors that increase Alaskans’ risks from heat, said Anne Zink, Alaska’s chief medical officer and an emergency room doctor.
She has noticed in her practice that hot days come with an increase in cases of shortness of breath, chest pain, dizziness, heat exhaustion, heat stroke, overheating in cars and similar problems, she said after listening to a presentation by Hahn in April at the Arctic Encounter Symposium in Anchorage. The elderly are most affected because they have more difficulty regulating their body temperatures, she said.
Hot or not, Alaskans are used to being physically active in the summer, Zink said. “We’re all manic all summer, right?” she said. And that can bring unexpected problems, as she saw in past summers, she said. “People would go up and hike the Butte or some trail that they were used to and then they would pass out. And then the family would bring them in,” she said, mentioning a popular hiking spot in Palmer.
Heat is often compounded with wildfire smoke, a known health hazard that this summer has plagued Fairbanks and some other regions – and that is increasing in frequency as the climate warms.
That leads to a double problem.
“When we have really hot, smoky days, you can’t go outside, you can’t go inside. Where’s the really safe place to be?” Hahn said.
One partial answer might be in shelters offering cool and clean. Fairbanks Memorial Hospital has in the past set aside one of its rooms as a clean-air shelter, and the clinic at Fort Yukon was equipped several years ago with a cooling system that established a similar shelter there, according to the Alaska Native Tribal Health Consortium. The government in Canada’s Yukon Territory has published instructions for residents who want to create their own clean-air shelters.
Anchorage, Alaska’s largest city, just finished a June that will be the second hottest on record – after the sweltering June of 2019 – and was also at times plagued by wildfire smoke.
Dry conditions conducive to wildfires have persisted for much of the state, with droughts in and around Anchorage, and in much of Interior and southwestern Alaska at the end of June, according to the national drought monitor.
As of June 30, wildfires around Alaska had burned over 1.6 million acres, just edging out the 2015 totals up to the period. The 2015 fire season wound up being the second biggest on record, with 5.1 million acres burned by summer’s end. In addition to the respiratory and cardiovascular risks posed by wildfire smoke, there are mental health effects, Hahn said.
She detailed those effects in a separate study that interviewed residents affected by the long-lasting and severe Swan Lake Fire of 2019, which burned for months and scorched nearly 170,000 acres on the Kenai Peninsula.
Mental-health problems ranged from short-term anxiety over the immediate emergency and feelings of claustrophobia because the roads were closed to stress over the economic hit from a lost tourist season to later grief, manifested after the fire finally ended in the fall, “when they went out to see what the aftermath looks like,” Hahn said. The effects were long-lasting. Even in 2021, “people mentioned that they were still being affected by the Swan Lake Fire,” she said.