It’s more than just a bad cold: influenza can also raise your risk of a heart attack shortly after an infection, medical experts are warning as the H3N2 strain spreads rapidly in Canada.

At the same time, flu season is coinciding with another risk factor for heart attacks – shovelling snow.

“Any time you get an infection, including a viral infection, there’s the release in your body of molecules that both trigger inflammation and sustain inflammation. And part of that is an increased tendency for your blood to clot,” said Dr. Fahad Razak, internal medicine physician at St. Michael’s Hospital and professor at the University of Toronto.

“That can have immediate effects within the weeks following an infection, resulting in things like strokes or heart attacks.”

Influenza brings with it an increased risk of heart attack and stroke, data shows.

People are four times as likely to have a heart attack and five times more likely to have a stroke in the month after laboratory-confirmed influenza, data published in the Journal of the American Heart Association in October shows.