Abstract 16087: Vigorous Exercise and Risk of Sudden Cardiac Death in Healthy Men
INTRODUCTION: Vigorous exercise is known to both trigger and protect against sudden cardiac death (SCD) at the time of exertion, and exertion-related SCD is more common among men. While habitual levels of moderate physical activity have been associated with lower long term risk of SCD among women, the impact of habitual vigorous activity on long term SCD risk in men is less clear.
METHODS: We assessed the association of vigorous exercise, updated over a 14 year period, and SCD among 21,317 men in the Physicians’ Health Study (PHS) who were initially free of cardiovascular disease. At 36 months and at 3 subsequent timepoints during follow-up, participants were asked about the frequency with which they engaged in a regular program of exercise vigorous enough to work up a sweat. Time-varying Cox proportional hazards models updated at each of these time points were used to determine the relative risk of SCD controlling for age and multiple confounders not thought to be in the causal pathway.
RESULTS: Over a mean follow-up of 22 years, 280 SCDs defined as death within one hour of symptom onset were confirmed. In age and multivariable adjusted models (Table, Models 1 and 2), the risk of SCD was U-shaped with the lowest risk of SCD among men who exercised 3-4 days per week (RR=0.77, 95% CI, 0.56-1.05; p for quadratic trend = 0.04). These results were modestly attenuated after controlling for potential intermediaries (Model 3).
CONCLUSION: In this cohort of apparently healthy men, the relationship between habitual vigorous exercise and overall risk of SCD is U-shaped with a nadir at 3-4 days per week. These data suggest that modest levels of vigorous exercise are safe over the long term and may even be protective against SCD in men.
- © 2013 by American Heart Association, Inc.