Cardiovascular effects of strenuous exercise in adult recreational hockey: the Hockey Heart Study.

BACKGROUND More than 500,000 men play "gentlemen's" recreational hockey in Canada, but the safety of this exercise has not been studied. Exercising at extremes of intensity has been associated with an increased risk of cardiac events. Our objective was therefore to determine baseline cardiac risk factors among adult recreational hockey players and to measure any cardiac abnormalities they experienced while playing hockey. METHODS We assessed baseline cardiac risk factors in 113 male volunteers recruited from a recreational hockey league. Each subject underwent holter electrocardiographic monitoring before, during and after at least one hockey game (maximum of 115 holter data sets). We used the data to assess exercise heart rate, arrhythmias and ST-segment changes and for correlation with symptoms and other predictors of fitness. RESULTS For all participants, maximum heart rate (HRmax) (mean 184 [standard deviation 11] beats/min) was greater than target exercise heart rate (calculated as 55% to 85% of age-predicted HRmax), and in 87 (75.6%) of the 115 holter data sets, the heart rate exceeded the age-predicted HRmax. The mean period for which heart rate exceeded 85% of the age-predicted HRmax was 30 (SD 13) min. For 80 (70.1%) of 114 data sets, heart rate recovery was poor. Nonsustained ventricular tachycardia was seen in data from 2 holter monitoring sessions and ST-segment depression in data from 15 sessions. INTERPRETATION The physical activity pattern that occurred during recreational hockey caused cardiac responses that might be dangerous to players' health. More specifically, the players exceeded target and maximum heart rates, had poor heart rate recovery after exercise, and had episodes of nonsustained ventricular tachycardia and ST-segment depression of uncertain clinical significance.