The Relationship Of Habitual Physical Activity With All-cause Mortality Among Obese Adults In US.

Abstract

Obesity is associated with increased risk for all-cause mortality. It is unclear if obese individuals need to engage in the same or more levels of physical activity in order to reap the benefits of an active lifestyle. PURPOSE: We test the hypothesis that regular habitual physical activity of 5 or more times a week among obese individuals, regardless of duration, intensity or mode, will be associated with lower all-cause mortality when compared to sedentary obese adults. METHODS: We used data from the Third National Health and Nutrition Examination Survey (NHANES III) conducted from 1988 to 1994. Participant records were linked to mortality data from the National Death Index to establish all-cause mortality. Detailed health information was obtained via a home interview and a medical examination. Measured weight and height were used to calculate obesity with a body mass index (kg/m2) > 30. Self-reported participation in leisure time physical activity was used to classify participants as inactive (0 times/wk), infrequently active (1-4 times/wk) and habitually active (5+times/wk). Cox proportional hazard was used to study the association of physical activity and all-cause mortality after controlling for age, socioeconomic status, smoking and chronic diseases. RESULTS: We studied 16,573 adults aged 20+ years. Both obesity and physical inactivity were independent risk factors of all-cause mortality. The prevalence of obesity in this group was 22.23%. We then studied the relationship between frequency of physical activity and all-cause mortality among obese persons. Obese individuals who exercised during leisure time habitually (5+ times/wk) had significantly lower risk (HR=0.74, 95% CI: 0.62,0.89) of all-cause mortality than the physically inactive obese group. CONCLUSION: For obese individuals, exposure to habitual physical activity 5+ times/wk is associated with lower all-cause mortality. All people should engage in habitual physical activity regardless of body weight.