Abstract 14772: Effects of Reallocating Time in Different Physical Activity Intensities and Sleep on Cardiovascular Disease Risk Factors in Asian American Women: A Cross Sectional Modeling Study

Abstract

Introduction: Physical activity (PA), sedentary behavior (SB) and sleep form the finite 24-hour day; changes to one behavior result in changes to the others. Little is known about how shifting the balance of time spent in these behaviors affects cardiovascular (CV) risk factors. The purpose of this study is to model the effects of changes in PA, SB and sleep on body mass index (BMI), waist circumference (WC) and blood pressure (BP) in Asian American women, who have elevated CV risk. Methods: Normotensive middle-aged Asian American women completed 7 days of hip and wrist actigraphy monitoring (Actigraph, GT3X and GT9X) to assess 24-hour activity. Total sleep time was identified using the Cole-Kripke algorithm with sleep diaries, and moderate-to-vigorous PA (MVPA), light PA and SB were classified by Freedson’s cut-points from wake time. Isotemporal substitution models were used to test effects of replacing 30 mins of each behavior with the others on BMI, WC and BP adjusting for age, education and comorbidity. Results: Data from 75 women were included (age=61.4±8.0, 57% college educated, median comorbidities=1[IQR=0-2]). On average, their days were composed of 0.5 hrs MVPA, 6.2 hrs light PA, 10 hrs SB and 5.3 hrs sleep (2.1 hrs non-wear time). In partition models, where all behaviors were entered simultaneously, more MVPA and sleep were associated with lower BMI and WC. In isotemporal substitution models that held total wear time constant (Table 1), replacing 30 mins SB with an equal amount of MVPA or sleep decreased BMI by 1.7 and 0.6 and WC by 4.1 and 1.2 cm. Replacing 30 mins light PA with MVPA or sleep decreased BMI by 1.9 and 0.9 and WC by 4.5 and 1.6 cm. None of the modeled behavior changes affected BP. Conclusion: These findings suggest that substituting 30 mins of SB or light PA with MVPA or sleep could significantly reduce Asian American women’s BMI and WC. Future studies should test the impact of behavioral interventions that promote these changes on CV risk in Asian American women.