Heart attacks often follow dramatic changes in outdoor temperature: study

New study suggests climate change may increase heart attack risk

Large day- to- day swings in temperature were associated with significantly more heart attacks. According to a study presented at the American College of Cardiology, some climate models link extreme weather events with global warming, and climate change could, in turn, lead to an uptick in the occurrence of heart attacks.

“Global warming is expected to cause extreme weather events, which may, in turn, result in large day- to- day fluctuations in temperature, and 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,” said Hedvig Andersson, a cardiology researcher at the University of Michigan and the study’s lead author.

There is a large body of evidence showing that outdoor temperature affects the rate of heart attacks, with cold weather bringing the highest risk, but most previous studies have focused on overall daily temperatures, according to the study, which is among the first to examine associations with sudden temperature changes.

Andersson added in the press release of the study, “while the body has effective systems for responding to changes in temperature, it might be that more rapid and extreme fluctuations create more stress on those systems, which could contribute to health problems, noting that the underlying mechanism for this association remains unknown.” Climate change is projected to lead to more extreme weather events, such as heat waves and cold snaps, depending on where someone lives, the researchers explained, along with an overall warming trend, said the study.

The study is based on data from more than 30,000 patients treated at 45 Michigan hospitals between 2010 and 2016. According to the study’s findings, all patients had received percutaneous coronary intervention, a procedure used to open clogged arteries, after being diagnosed with ST- elevated myocardial infarction, the most serious form of heart attack.

To reach their findings, the scientists calculated temperature fluctuations preceding each heart attack based on weather records for the hospital’s ZIP code. Daily temperature fluctuation was defined as the difference between the highest and lowest temperature recorded on the day of the heart attack.

“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,” said 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,” he added.