Some U.S. studies have shown there tends to be a spike in heart attacks and arrhythmias at Christmas and New Year's.
"We've known when we look across a large population that the incidence of heart events — heart attacks, admissions to hospital for heart problems — does tend to increase, does tend to peak over the Christmas season," said Dr. Andrew Pipe of the University of Ottawa Heart Institute.
"And it's felt that there are probably a number of factors that contribute to this, but they're all factors which, combined with risk factors for heart disease or pre-existing heart disease, can conspire to produce this increase in cardiac events."
Overeating, drinking too much alcohol, reduced exercise and emotional stress at this time of year could play a role.
Increased intake of alcohol can contribute to the likelihood of people having disorders of their cardiac rhythm, the most common of which is called atrial fibrillation, said Pipe.
Many patients during the holiday period already have a known heart condition, but some people might not be aware they're at risk.
"We know that people eat to excess, drink to excess, winter ... delivers its first blows at this time," said Pipe, the institute's chief of the division of prevention and rehabilitation.
"So individuals may be suddenly deciding that they need to shovel their driveway in order that they can get to Aunt Mary's for the Boxing Day feast, and they haven't shovelled the driveway in years, they're unfit, they've got risk factors and obvious calamities can occur."
The heart institute recommends scheduling some down time to avoid stress, and staying away from foods with excessive amounts of salt and fat.
It also advises getting a flu shot and making lifestyle changes, such as exercising more regularly and quitting smoking.
An unfortunate consequence of the holiday season is that someone having symptoms of a heart attack might not want to disrupt the family celebration and draw attention to their pain, Pipe said.
"Anyone who has unusual chest pain, particularly chest pain which is squeezing or feels like a pressure on your chest that radiates to the jaw or to the shoulder or to the arms, should immediately have themselves taken to a hospital emergency department or call 911," Pipe said in an interview from Ottawa.
"Christmas and the holiday period is not the time to wonder whether the symptoms that you're experiencing are something that need to be taken care of. When in doubt, find out."
Tips from the institute also say that people with known risk factors — such as smoking, high blood pressure and elevated cholesterol levels — should take daily walks, for instance, but avoid over-exerting themselves through activities like heavy snow shovelling.