Effects of Sleep Loss on Endothelial Function and Cytokine Levels in Internal Medicine Residents

Context: Sleep loss is associated with increased blood levels of interleukin-6 (IL-6) and C-reactive protein (CRP). Medical residents are often deprived of normal sleep during extended work shifts, but the effects of work-related sleep loss on biomarkers of vascular inflammation and function are unknown.

Objective: We sought to test the hypothesis that sleep loss during extended work shifts during medical training is associated with increased circulating levels of pro-inflammatory biomarkers and evidence of vascular dysfunction.

Design: Outcome measures were assessed after extended 30-hour work shifts and non-extended 6-hour work shifts in a single-blind, randomized crossover design.

Setting: University hospital medical intensive care unit

Patients or Other Participants: Twenty-two healthy medical residents were studied during a medical intensive care unit rotation.

Main Outcome Measure(s): Sleep related cytokines (interleukin-6 and tumor necrosis factor), serum markers of vascular inflammation (C-reactive protein), and flow-mediated dilation in the brachial artery.

Inclusion criteria

• Medical resident in MICU rotation
• Non-smoker
• Body mass index <28 kg/m2

Exclusion criteria

• Systolic blood pressure >140 mmHg; Diastolic blood pressure >90 mmHg
• Known history of diabetes mellitus, hypertension, hyperlipidemia
• Known history of acute or chronic inflammatory or infectious disease
• Known history of sleep disturbance unrelated to work
• Pregnancy