Abstract
INTRODUCTION: Sleep, sedentary behavior, and physical activity are each independently associated with cardiovascular health (CVH). It is unknown how substituting time in sedentary behavior with sleep or physical activity affects overall CVH. METHODS: Data for this analysis were taken from the Multi-Ethnic Study on Atherosclerosis Sleep Ancillary Study. Eligible participants (N = 1718) wore Actiwatch accelerometers for 24 h and had at least 3 d of valid accelerometry. The American Heart Association's Life's Simple 7 was used to represent the CVH score after excluding the physical activity component, with higher scores indicating more favorable CVH. Isotemporal substitution modeling was conducted to examine the effect of substituting 30 min of sedentary time for an equivalent amount of sleep, light-intensity physical activity (LIPA), or moderate to vigorous physical activity (MVPA). RESULTS: Substituting 30 min of sedentary time to sleep, LIPA, and MVPA was associated with a significantly higher CVH score [β (95% confidence interval) = 0.077 (0.056), 0.039 (0.033), and 0.485 (0.127), respectively]. Substituting 30 min of sedentary time to sleep was associated with lower body mass index (BMI). Substituting 30 min of sedentary time to LIPA was associated with higher diastolic blood pressure and total cholesterol, and lower BMI. Substituting 30 min of sedentary time to MVPA was associated with lower systolic and diastolic blood pressure, and lower BMI. CONCLUSIONS: Sleep, LIPA, and MVPA are all associated with more favorable overall CVH and several key risk factors for cardiovascular disease. These findings underscore the importance of lifestyle modifications in improving CVH.