I’ve noticed that my patients suffer more heart attacks and other coronary incidents during flu season, though I couldn’t quite explain why. Now the science is catching up with those observations.

It’s long been known that heart disease is a risk factor for developing serious flu complications. Among adults hospitalized with the flu in recent seasons, heart disease was one of the most common chronic conditions reported. About half of the adults who are hospitalized with the flu also have heart disease.

But a growing body of research suggests that influenza infection can put people at increased risk for acute cardiovascular events such as heart attack and stroke — a finding the American Heart Association highlighted last winter. This evidence has been steadily mounting.

According to one study, people were six times more likely to have a heart attack in the week after being diagnosed with flu. The research, published in  in the Annals of Internal Medicine, reported that sudden, serious cardiac events are more common in adults hospitalized with flu.

This study, which looked at more than 80,000 adult patients hospitalized with the flu over eight seasons, found that almost one in eight (12 percent) patients had experienced an acute cardiac event such as heart failure or coronary artery disease. Of those people, 30 percent were admitted to the ICU and 7 percent died while in the hospital.

In addition, a study published in The Journal of Infectious Diseases found that even mild illness caused by influenza virus infections are associated with a twofold increase in the risk of acute cardiovascular events in older patients.

So the flu not only makes you feel bad, it jeopardizes your heart as well.