0204 Associations of Reallocating Sedentary or Activity Time to Sleep on Body Weight in Postpartum Women

Abstract

Abstract Introduction In the postpartum period, decreased sleep time is associated with increased postpartum weight retention. Increasing sleep time in the postpartum period may be beneficial; however, increasing total sleep time will reduce the time available for light physical activity (LPA), moderate to vigorous activity (MVPA), or sedentary behavior (SED). Therefore, the purpose of this study was to examine the associations of reallocating time in SED, MVPA, and LPA to sleep with body weight in postpartum women. Methods Women (n=130) who gave birth to a singleton infant at ≥37 weeks gestation participated in the study. At 6-8 weeks, 6 months, and 12 months postpartum wrist actigraphy was used to measure total sleep time and hip actigraphy was used to measure SED, LPA, and MVPA. Women were instructed to wear the monitors for 7 days and maintain their normal daily activities. Weight was measured at each timepoint using a calibrated scale. Isotemporal substitution models were preformed to examine the association of reallocating time to sleep from SED, LPA, and MVPA on body weight. Results At 6-8 weeks, reallocating ten minutes of SED or MVPA to sleep was associated with a -0.54 kg (p=0.0223) and -3.33 kg (p=0.0091) change in body weight, respectively. At 6 months, reallocating ten minutes of SED or MVPA to sleep was associated with a -0.931 kg (p=0.0069) and -2.97 kg (p=0.0434) change in body weight, respectively. At 12 months, reallocating ten minutes of SED to sleep was associated with a -1.21 kg (p=0.0166) change in body weight. Reallocating time from MVPA to sleep was not associated with changes in body weight at 12 months. Reallocating time from LPA to sleep was not associated with changes in body weight at any timepoint. Conclusion Throughout the first year postpartum, reallocating time from SED to sleep was associated with decreases in body weight. Surprisingly, reallocating time from MVPA to sleep was also associated with a decrease in body weight at 6-8 weeks and 6 months postpartum. These results suggest the relative importance of the behaviors comprising the 24-hour day to body weight may be changing over the first year postpartum. Support (if any) NIH Grant R21MD012740