Cold Weather Could Predict an Increase in Heart Attacks Three Days in Advance

Humans have done a great job of building artificial infrastructure to insulate ourselves from the natural world—cities, homes, air conditioning, etc. We’re so good at constructing comfort-maximizing bubbles that it’s easy to forget we’re still very much at the mercy of Mother Nature, in big ways and small. For example, a new study published in Public Health recently found that even the incidence of heart attacks may be under the sway of the weather.

Cardiovascular diseases have long been known to peak during the colder months in both the northern and southern hemispheres. In fact, the holidays can be a particularly deadly time for heart attacks here in the United States. To tease apart the different potential contributing factors, a team of Hungarian cardiac specialists compared data on cardiac arrests with meteorological measures like temperature, wind speed, atmospheric pressure, and more.

Altogether, their dataset included more than 114,000 out-of-hospital heart attack cases in Hungary between November 2018 and December 2023. Read more: “Night Owls Could Be Putting Their Heart Health at Risk” They found that cardiac arrests rose by nearly 18 percent during the winter, and that temperature was the greatest contributor to the rise. Importantly, it wasn’t just deep plunges in temperature that showed an association with increased, but incremental changes, as well.

For every 1.8 degree Fahrenheit decrease in ambient temperature, heart attacks rose by 1.4 percent. Additionally, the data showed a three-day lag, so when the temperatures dipped, heart attacks inched up a few days later. According to the team, these findings can allow emergency services time to prepare and vulnerable populations the opportunity to protect themselves.

Why do heart attacks increase during winter? Well, frigid temps trigger a lot of physiological reactions including vasoconstriction, a higher cardiac workload to maintain core body heat, increased adrenaline production and other hormonal changes, and more. All of these can take their toll on the heart (not to mention the stress of the holidays).

The team says the three-day lag in the uptick means these stressors likely accumulate. So if you’re someone with heart disease or other risk factors, remember to stay on alert this winter. Subscribe to our free newsletter.