What the puck! Could watching a hockey game cause a heart attack?

Could watching a hockey game increase your risk of having a heart attack?

That’s the question researchers in Canada have tried to answer in a new study published in the Canadian Journal of Cardiology Thursday.

The researchers’ goal was to analyze hospital admissions to the Montreal Heart Institute between 2010 and 2014 to see whether more patients were treated for heart attacks when the city’s ice hockey team, the Montreal Canadiens, played a match.

Although admissions for heart attacks didn’t change on the day of a hockey game, the researchers found it did increase -- just a bit -- the day after a game. But not everyone was skating on thin ice; the effect was only seen in men below the age of 55. Both older men and women appear to be immune to the hockey effect.

While hockey fans may say their hearts are broken when their team loses, the research shows the opposite. Hospital admission rates increased most when the team won a match at home. After home wins, there was a 40 percent increase in hospital admissions among men under the age of 55.

How do the scientists explain the findings?

They suggest that the emotional stress of watching a hockey game could cause increased stress on the heart, triggering an event such as a heart attack.

“The Montreal Canadiens is known for its extremely loyal and enthusiastic fan base. This historical role of the city of Montreal might explain in part the association” said Dr. Hung Q. Ly, the study’s lead investigator and an interventional cardiologist at the Montreal Heart Institute.

Research published last year showed that spectators’ heart rates more than doubled while watching a hockey game. This was most pronounced when watching a game in person compared to on television.

But this latest research is more puzzling. Neither overtime losses nor shootout wins changed the rate of hospital admissions, suggesting the extra heart attacks might not be caused by the stress of watching a game alone.

Importantly, the findings only show an association between hockey games and admission rates, so it’s not known whether watching hockey games actually caused any of the health problems in the study. A number of other factors including alcohol consumption, drug-taking and sleep deprivation -- all of which could be related to a hockey game -- might be responsible instead.

In fact, we don’t even know how many of the 2,199 patients who suffered a heart attack in the study were actual hockey enthusiasts who recently watched a game.

The study, published in the Canadian Journal of Cardiology, builds on similar research from other sports events across the world. In England, for example, researchers found that the rates of heart attack increased after the national soccer team was knocked out of the 1998 World Cup.

But, perhaps, different fans experience different effects when watching a sport. When the French national team played in the same competition, the number of heart attacks decreased in the country.

It’s still too early to tell whether watching a sports game has any effect on our health. For now, doctors will have to put the idea on ice before making any recommendations to patients.

George Gillett is a resident affiliated with the University of Oxford, working in the ABC News Medical Unit.