Hockey fans with cardiac disease might want to watch their heart rate a little more closely this winter, a team of Canadian researchers advises.

In a study published by the Canadian Journal of Cardiology, lead author Paul Khairy, MD, PhD, and colleagues studied a handful of ice hockey lovers and monitored their heart rates during live and televised games, ultimately finding heart rates more than doubled during exciting games.

Hockey may not have been studied before in this capacity, but there’s plenty of data proving the adverse cardiac effects intense sports can have on their viewers. In one example, Khairy and co-authors cited a study of 10 Scottish soccer fans whose heart rates increased by 23 beats per minute (bpm) just after their supported team scored a goal. One British study conducted in the 1990s showed mortality attributable to heart attack and stroke increased significantly in men on the days a local soccer team lost a home game.

“The link between sporting events and adverse cardiovascular health has been previously studied in soccer spectators, albeit with limited psychological data,” Khairy and colleagues wrote in the study. “In 2000, Dutch investigators reported an excess in cardiovascular deaths in men 45 years of age or older on the day that the Dutch soccer team was eliminated by France in a penalty shootout during the European soccer championship.”

Compared to the days leading up to that game, the authors wrote, mortality from coronary artery disease and stroke more than doubled.

The researchers collected a small group of participants—10 were recruited to watch a live game and 10 watched a game on TV—who’d had no known heart disease or complications in the past. Khairy’s team used demographic variables, quick questionnaires, medical history, a fan passion score and three-channel digital cardiac Holter monitors to quantify cardiac changes in the subjects over the span of each game. They also took into account different game-related factors, like team rankings, shots, goals, fights, injuries, penalties and overtime.

The middle-aged participants, who had an average resting heart rate of 60 bpm, were monitored for around 250 minutes total. Overall, Khairy and colleagues found their cumulative heart rates increased by a median of 92 percent, jumping from the baseline of 60 bpm to 114 bpm during the course of the game.

Televised games were associated with a 75 percent increase in heart rate, the researchers found, but the median increase in heart rate during a live game climbed to 110 percent, resulting in a 42.5 percent increase in heart rate in subjects watching games live at the Bell Centre.

This increase is equivalent to heart rate during vigorous physical stress, the authors wrote. During a televised game, heart rates were equivalent to moderate physical stress. While game periods, including overtime and scoring opportunities for and against teams, resulted in peak heart rates, fan passion scores appeared to have nothing to do with rate results.

“The emotional excitement related to sports, like other stressful circumstances, results in heightened sympathetic activity with attenuated cardiac vagal outflow,” Khairy and co-authors wrote. “However, cardiovascular events triggered by sporting events appear to be far more common in individuals with known coronary artery disease.”