The importance of vigorous-intensity, leisure-time physical activity in reducing cardiovascular disease mortality risk in the obese

Objective: To investigate the role of vigorous-intensity leisure-time physical activity in reducing cardiovascular disease (CVD) mortality risk in the obese. Methods: Trained interviewers assessed physical activity and body mass index (BMI) in 59,005 adult participants (57±12 years of age [mean±SD]; 46.5% male) in the household based surveillance studies, Health Survey for England and Scottish Health Survey. Mortality was ascertained from death certificates. Data were collected from January 1994 to March 2011. Cox proportional hazards models were adjusted for age, sex, smoking habit, total physical activity, longstanding illness, prevalent CVD, and occupation. Results: There were 2,302 CVD deaths during 532,251 person-years of follow-up (9±4 years). Some 25% of participants were categorized as obese (BMI ≥30 kg·m-236 ). Leisure-time physical activity was inversely associated and BMI was positively associated with CVD mortality. Compared to those who reported meeting physical activity guidelines, including some vigorous-intensity physical activity, and who had a normal BMI (18.5-24.9 kg·m-239 ) (reference group), CVD mortality hazard ratio was not significantly different in the obese who also reported meeting physical activity guidelines, including some vigorous-intensity physical activities (1.25; 95% confidence interval: 0.50, 3.12). Compared to the reference group, CVD mortality hazard ratio was more than twofold in the obese who reported meeting physical activity guidelines, including only moderate-intensity physical activities (2.52; 95% CI: 1.15, 2.53). Conclusion: This large, statistically powerful study suggests that vigorous-intensity leisure time physical activity is important in reducing CVD mortality risk in the obese.