Does the weather actually affect your risk of experiencing a heart attack? An association between the two has been observed by researchers as far back as the 1920s.

Namely, it has been suggested the colder the weather, the higher the risk of heart attack. Now, a new study explores the possible mechanisms that may contribute to this heightened risk.

Said to be the largest of its kind, the research looked at 15 years of weather data and the incidence of heart attacks in Sweden over the same period. The findings were published in JAMA Cardiology on Oct. 24.

"People have been talking about weather and heart attacks for about 100 years," said lead author Dr. David Erlinge, who is the head of cardiology at Lund University in Sweden. "With our robust data, we can separate out many more factors than just the cold."

The highest incidence of heart attacks was observed on days with below-freezing temperatures which is under 32 degrees Fahrenheit. The rate of heart attacks decreased as the temperatures rose close to 40 degrees.

But does the cold temperature itself play a direct role here? It is definitely a possibility according to Dr. Erlinge.

"Cold and windy weather leads to a contraction of blood vessels in the skin to conserve energy and temperature," he explained. "That increases the workload of the heart, increasing the risk of a heart attack."

But the findings also present another theory. This correlation between cold weather and heart attacks was not found in the northern parts of the country, which is the coldest region. So, rather than the extreme cold, it may be the extreme fluctuation in temperature that affects heart health.

Among other factors, behavioral patterns were also considered. For example, shoveling snow could be a dangerous activity for older adults who are not used to such levels of strain during the rest of the year. Less exposure to sunlight, changes to dietary patterns, higher likelihood of flu, and seasonal affective disorder were also noted as potential influencers.

Future studies may consider looking at regions like the United States characterized by more variations in weather. The average age of participants in the study was 72, so it may also be worth studying the association in younger populations.

"Many older people move to warm, sunny places in retirement," Dr. Erlinge said. "Our study indicates that that is a good idea."

For people who are at risk of suffering heart attacks, due to family history or past heart attacks, he advised wearing layers of warm clothes and staying inside the house when temperatures dip low. Experts also recommend learning how to perform CPR, knowing the warning signs of a heart attack, and taking adequate breaks when working.