0226 Relationships Between Physical Activity and Cardiovascular Risk Factors in Habitual Short Sleepers

Abstract Introduction Short sleep duration increases cardiovascular and metabolic risks, leading to an increase in cardiovascular mortality. Increasing sleep duration mitigates metabolic impairments. However, alternative strategies to reduce cardiometabolic risks in habitual short sleepers are lacking. Generally, increasing physical activity (PA) is recommended to reduce such risks, but its potential impact in habitual short sleepers is not completely understood. This study aimed to explore the relationship between wearables derived PA, and cardiometabolic risk factors in habitual short sleepers. Methods Sleep and PA patterns were objectively determined by a 7-day accelerometry recording in men (n=17) and women (n=25) aged 31.0±7.3 years (mean±SD) with habitual short sleep (i.e. < 390 min/night) and BMI of 28.9±3.5 kg/m2. Anthropometric were determined and body composition was assessed by whole-body DXA scan. Fasting blood was drawn to measure glucose, insulin, glycated hemoglobin, and lipid profile. Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was calculated. Pairwise correlations were performed between steps/day and the different measurements assessed in this study. Results Average sleep duration was 340±41 min/night with a sleep efficiency of 90±4%. Participants spent 11.3±1.4 hours/day in sedentary time, 62.6±34.6 min/day to perform moderate-to-vigorous PA (MVPA) and walked 7875±2287steps/day. Insulin sensitivity (HOMA-IR) varied widely ranging from 0.43 to 5.87. There was no relationship between any objective measures of sleep and the number of steps/day (p>0.34). No relationship was observed between steps/day and BMI, or lipid profile (p>0.26), However, a negative correlation was observed between steps/day and body fat percent (R=-0.36, p=0.02), as well as fasting insulin concentration (R=-0.34, p=0.03). Further, steps/day were associated with higher fasting plasma glucoses (R=0.53, p< 0.01) and a tendency for a decreased HOMA-IRs (R=-0.28, p=0.07). Conclusion Habitual PA as determined by steps/day is associated with lower body fat percentage and insulin resistance in habitual short sleepers. Future interventional studies are needed to examine if increasing daily step count may partly mitigate the detrimental metabolic impact of short sleep. Support (if any) This work was supported by the NIH Grant [R01HL166306 to PS].