Beneficial associations of low and large doses of leisure time physical activity with all-cause, cardiovascular disease and cancer mortality: a national cohort study of 88,140 US adults

Background Evidence on the role of very low or very high volumes of leisure time physical activity (PA) on the risk of all-cause and cause-specific mortality is limited. We aimed to examine the associations of different levels of leisure time PA with the risk of all-cause, cardiovascular disease (CVD) and cancer-specific mortality.Methods Data were from 12 waves of the National Health Interview Surveys (1997{\textendash}2008) linked to the National Death Index records through 31 December 2011. A total of 88 140 eligible participants aged 40{\textendash}85 years were included.Results Compared with inactive individuals, those performing 10{\textendash}59 min/week of PA had 18\% lower risk of all-cause mortality (hazard ratio (HR): 0.82, 95\% confidence interval (CI): 0.72{\textendash}0.95). Those who reported 1{\textendash}2 times (150{\textendash}299 min/week) the recommended level of leisure time PA had 31\% (HR: 0.69, 95\%CI: 0.63{\textendash}0.75) reduced risk of all-cause mortality. Importantly, the continued benefits were observed among those performing leisure time PA 10 or more times (>=1500 min/week) the recommended minimum level (HR: 0.54, 95\% CI: 0.45{\textendash}0.64). For 10{\textendash}59, 150{\textendash}299 and >=1500 min/week of PA, the corresponding HRs (95\% CIs) for CVD-specific mortality were 0.88 (0.67{\textendash}1.17), 0.63 (0.52{\textendash}0.78) and 0.67 (0.45{\textendash}0.99), respectively: for cancer-specific mortality were 0.86 (0.66{\textendash}1.11), 0.76 (0.64{\textendash}0.89) and 0.53 (0.39{\textendash}0.73), respectively. In addition, there was a larger reduction in all-cause and cause-specific mortality for vigorous vs. moderate intensity PA.Conclusions We found that beneficial association between leisure time PA and mortality starts from a low dose. Doing more vigorous exercise could lead to additional health benefits.