Previous studies have linked watching sporting events to an increased risk of heart attack and sudden death among spectators, especially for people with existing coronary artery disease. The new research involved 20 adults living in Montreal who had no history of heart disease. They gave information about their general health and filled out a “fan passion” questionnaire to determine how invested they were in their local National Hockey League team, the Montreal Canadiens.

Then, researchers from the University of Montreal measured everyone’s pulse while they watched a Canadiens game. Half watched on television, and half attended the game in an arena. They found that TV viewers’ heart rates increased by an average of 75%, and game attendees’ heart rates increased by 110%.

That’s about equal to the heart-rate bump seen during moderate-to-vigorous exercise, the authors say. Participants’ heart rates stayed above the threshold for moderate physical activity for about 39 minutes when watching a game on television. For those in the arena, heart rates stayed above the moderate-activity threshold for 72 minutes, and above the vigorous-activity threshold for almost 13.

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In total, spectators’ heart rates increased by an average of 92% during the hockey games, from a resting heart rate of about 60 beats per minute to a maximum of 114. Peak heart rates occurred during scoring opportunities, both for and against the Canadiens, and were noted throughout the game—not just at the end or in overtime.

“It is not the outcome of the game that primarily determines the intensity of the emotional stress response,” the authors wrote in their paper, “but rather the excitement experienced while viewing high-stakes or high-intensity portions of the game.”

Somewhat surprisingly, it didn’t seem to matter how passionate fans were about the team. Their heart-rate fluctuations weren’t affected by where they fell on the “fan passion” scale, or what gender they were, either. The authors note, however, that the scale was adapted from studies involving soccer fans, and that a questionnaire designed specifically for hockey fans may have revealed a more accurate relationship.

Viewing a hockey game can be a source of “intense emotional stress,” the authors wrote in their paper, which may temporarily increase markers of inflammation and blood vessel constriction for people who already have heart problems. And while no harmful effects were observed in their healthy sample of participants, the authors raise the possibility that such a stress response could trigger a cardiac event.

In an accompanying editorial, researchers from Zuckerberg San Francisco General Hospital and the University of Montreal say that the true role of cardiovascular-event “triggers,” including sporting events, is not entirely clear. “It is possible that triggers precipitate [cardiovascular] events that are about to occur soon anyway,” they write. “If so, preventive strategies directed specifically at triggers would not be particularly helpful.”

They also write that watching hockey “is only one of several activities that are important for quality of life but are associated with some risk,” (exercise and sex are two others) and that “avoiding all triggers equates to avoiding life itself and is not a viable strategy.”

Still, they say that doctors should speak with their at-risk patients about the potential dangers of watching exciting sporting events. Having defibrillators in place at sporting arenas will also save lives, they add.

The editorial authors conclude that a Stanley Cup victory for the Montreal Canadiens or another hometown team would “undoubtedly” cause a spike in cardiovascular events among Canada’s die-hard hockey fanbase. “Unfortunately that risk does not seem imminent,” they write, since no Canadian-based hockey team has won the championship since 1993.