High Leisure-Time Physical Activity Is Associated With Reduced Risk of Sudden Cardiac Death Among Men With Low Cardiorespiratory Fitness

Background: We studied the independent and joint associations of leisure-time physical activity (LTPA) and cardiorespiratory fitness (CRF) with the risk of sudden cardiac death (SCD) among middle-aged men. Methods: The participants were 2656 randomly selected men aged 42-60 years at baseline who were followed for 19 years. LTPA was assessed using a questionnaire modified from the Minnesota LTPA Questionnaire and CRF using a respiratory gas exchange analyzer during maximal exercise test. The participants were divided into 4 groups according to the level of LTPA and CRF dichotomized at the lowest tertiles. Results: Men with low CRF had a 1.6 (95% confidence interval [CI], 1.1-2.3; P = 0.011) times higher risk of SCD than men with high CRF after adjustment for conventional risk factors. Men with low LTPA had a 1.4 (95% CI, 1.0-2.0; P = 0.032) times higher SCD risk than men with high LTPA after these adjustments. Men with low CRF and low LTPA had a 2.2 (95% CI, 1.4-3.3) times higher SCD risk than men with high CRF and high LTPA adjusting for conventional risk factors (P = 0.044 for interaction). Conclusions: It seems that low LTPA increases the risk of SCD particularly among men with low CRF but the level of LTPA does not modify the incidence of SCD among men with high CRF.