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Cross-country skiers at heightened risk for arrhythmias
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Cross-country skiers who competed in a 90-km race in Sweden showed heightened risk for the development of arrhythmias, according to results from a large cohort study. The findings may shed light on how very high levels of physical activity pose risks for arrhythmia.
Researchers identified participants in the Vasaloppet (n=52,755; 10% women), one of the world’s most challenging cross-country skiing events, between 1989 and 1998. Follow-up through 2005 revealed that risk for developing AF or bradyarrhythmia was higher in skiers who competed in the race more often or finished with faster times.
“We found that those who completed five or more races in a period of 10 years had a 30% higher risk of developing any arrhythmia than those who did one race only,” study researcher Kasper Andersen, MD, a cardiologist at Uppsala University Hospital in Sweden, said in a press release. “Similarly, skiers who had the fastest finishing time relative to other participants also had a 30% higher risk of developing any arrhythmia in subsequent years.”
According to the researchers, only a few small studies have examined the effect of endurance exercise on heart rhythm disturbances, which tended to examine sedentary people, or were designed to compare physically inactive vs. physically active individuals.
The primary outcome of the study was hospitalization for any arrhythmia. Among the participants, 919 (1.74%) experienced some sort of arrhythmia during follow-up. After adjustment for age, education and occupational status, the researchers observed a higher incidence of any arrhythmia with increasing number of races completed (HR=1.3; 95% CI, 1.08-1.58 for at least five completed races vs. one completed race) and with faster finishing time (HR=1.3; 95% CI, 1.04-1.62 for 100% to 160% vs. >240% of winning time). Similar findings were reported for risk for AF (HR=1.29; 95% CI, 1.04-1.61 for number of races; HR=1.2; 95% CI, 0.93-1.55 for finishing time) and bradyarrhythmias (HR=2.1; 95% CI, 1.28-3.47 for number of races; HR=1.85; 95% CI, 0.97-3.54 for finishing time).
The researchers reported no association between finishing time or number of completed races with increased risk for supraventricular tachycardia, ventricular tachycardia/ventricular fibrillation/cardiac arrest.
For more information:
Andersen K. Eur Heart J. 2013;doi:10.1093/eurheartj/eht188.
Disclosure: One researcher is on the scientific advisory board for Itrim. The other researchers report no relevant financial disclosures.