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Short sleep, cardiovascular disease, and type 2 diabetes are all highly prevalent health issues in modern society. Previous findings demonstrate that obtaining short sleep is linked to an increased risk of cardiometabolic diseases such as type 2 diabetes and heart disease. However, the mechanisms underlying how short sleep duration affects these health issues are not fully understood. C-reactive protein (CRP) is an inflammatory marker which has been linked to a greater risk of cardiovascular disease, but prior research has found conflicting information on whether short sleep significantly affects CRP levels. Thus, the current project aims to investigate the impact of short sleep on CRP levels as well as on insulin sensitivity and blood pressure to better understand the potential mechanisms by which short sleep duration is linked to adverse cardiovascular risk. The project utilized data from the parent study, "Biomarkers and Altered Metabolic Pathways during Sleep Loss." The study recruited healthy individuals aged 18- 35 who chronically received short sleep (<6.5h per night). After baseline assessments, participants completed a 4-week intervention aiming to increase their time in bed by 2 hours per night. Sleep duration and physical activity data were collected throughout the study. Insulin sensitivity, CRP, blood pressure, and fasting glucose and insulin levels were compared at baseline and sleep extension. Of the 20 participants included in the current analysis, average sleep duration was 340 ± 83 (± SD) minutes per night at baseline and significantly increased (p < 0.001) by 61 ± 11 (± SE) minutes during sleep extension. Insulin sensitivity after sleep extension was lower than baseline. Specifically, in a linear mixed-effects regression model adjusting for sex, body weight, and moderate-to-vigorous physical activity (MVPA), the Matsuda index significantly decreased (P < 0.05) by 1.2 ± 0.5 (SE) and HOMA-IR significantly increased (P < 0.05) by 0.4 ± 0.2 (SE) from baseline to extension. No significant differences between segments were observed for CRP, blood pressure, or fasting glucose and insulin levels. Systolic blood pressure was higher for men than for women at baseline, suggesting that among individuals habitually receiving short sleep, men may be at higher risk of hypertension. Our current findings highlight that otherwise healthy young adults with low overall risk of cardiometabolic disease do not show physiological benefit from a 4-week sleep extension intervention. The current intervention was feasible and increased sleep duration by ~1 hour per night. Longer term interventions in higher-risk populations such as older adults with obesity are needed to more comprehensively quantify the impact of sleep extension on risk of cardiometabolic disease. |
