Heart attacks are more prevalent after a dramatic temperature swing outside, a new study indicates. Now with scientists pointing to more unstable weather events and patterns occurring as a result of climate change, researchers say more people around the world will be at risk of suffering serious cardiac events.
The research is among the first to show how significant changes in daily weather conditions can affect a person’s heart health.
“Global warming is expected to cause extreme weather events, which may, in turn, result in large day-to-day fluctuations in temperature,” says Hedvig Andersson, a cardiology researcher at the University of Michigan and the study’s lead author, in an American College of Cardiology release. “Our study suggests that such fluctuations in outdoor temperature could potentially lead to an increased number of heart attacks and affect global cardiac health in the future.”
Past studies have already shown links between outside temperatures and the rates of heart attacks in populations, but most of them only studied the daily overall temperature, not large fluctuations in temperature.
Andersson says that while his team can’t say exactly why temperature fluctuations cause more heart attacks, “it might be that more rapid and extreme fluctuations create more stress on those systems, which could contribute to health problems.”
The survey was based on data collected from more than 30,000 patients who received care at 45 hospitals between 2010 and 2016. All of these patients were diagnosed with ST-elevated myocardial infarction, the deadliest form of heart attack, then received percutaneous coronary intervention, a standard procedure used in these cases to open clogged arteries.
After calculating the temperature fluctuation before each patient’s acceptance to a hospital, the researchers found that the risk of heart attack increased by five percent for every nine-degree Fahrenheit increase in temperature differential. The effect was particularly noticeable when major temperature swings occurred on warmer days, and greatest when temperature swings dropped or grew by 45 degrees or more.
To isolate the effects of temperature fluctuation, the researchers adjusted their models for precipitation amounts, day of the week, and seasonal trends.
“Generally, we think of heart attack risk factors as those that apply to individual patients and we have, consequently, identified lifestyle changes or medications to modify them. Population-level risk factors need a similar approach,” says Dr. Hitinder Gurm, professor of medicine and associate chief clinical officer at Michigan Medicine and the study’s senior author. “Temperature fluctuations are common and [often] predictable. More research is needed to better understand the underlying mechanisms for how temperature fluctuations increase the risk of heart attacks, which would allow us to perhaps devise a successful prevention approach.
The research will be presented at the American College of Cardiology’s 67th Annual Scientific Session on March 10th.