Light-Intensity Physical Activity and Life Expectancy: National Health and Nutrition Survey

Introduction: Quantifying the years of life gained associated with light-intensity physical activity may be important for risk communication in public health. Because no studies have examined the role of light-intensity physical activity in life expectancy, this study aims to quantify the years of life gained from light-intensity physical activity in a population-based U.S. sample. Methods: This study used data from 6,636 participants in the National Health and Nutrition Examination Survey (2003-2006). Analyses were conducted in 2020. Light-intensity physical activity was categorized into low, medium, and high on the basis of tertiles, and survival models were applied to estimate the years of life gained from each light-intensity physical activity group. Analyses were repeated in participants with moderate-to-vigorous physical activity above or below the median. Results: During a mean follow-up of 11 years and at 55,520 person-years, 994 deaths were recorded. At age 20 years, participants with low, medium, and high light-intensity physical activity had a predicted life expectancy of 53.92 (95% CI=46.66, 61.18), 58.16 (95% CI=52.10, 65.22), and 58.44 (95% CI=51.29, 65.60) years, suggesting significant years of life gained from medium and high levels of light-intensity physical activity of 2.89 (95% CI=0.90, 4.12) and 3.07 (95% CI=0.84, 5.30) years. The corresponding years of life gained at age 45 years and 65 years were 2.51 (95% CI=0.40, 5.47) and 1.52 (95% CI=0.54, 2.50) years for the medium light-intensity physical activity group and 2.66 (95% CI=0.80, 4.52) and 1.62 (95% CI=0.49, 52.75) years for the high light-intensity physical activity group. This association was significant in participants with moderate-to-vigorous physical activity below the median but not for those with moderate-to-vigorous physical activity above the median. Conclusions: Light-intensity physical activity may extend life expectancy. Given the low prevalence of moderate-to-vigorous physical activity in populations, physical activity promotion efforts may capitalize on emerging evidence on light-intensity physical activity, particularly among the most inactive groups. (C) 2021 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.