title: Morning Circadian Misalignment during Short Sleep Duration Impacts Insulin Sensitivity.
abstract: Short sleep duration and circadian misalignment are hypothesized to causally contribute to health problems including obesity, diabetes, metabolic syndrome, heart disease, mood disorders, cognitive impairment, and accidents. Here, we investigated the influence of morning circadian misalignment induced by an imposed short nighttime sleep schedule on impaired insulin sensitivity, a precursor to diabetes. Imposed short sleep duration resulted in morning wakefulness occurring during the biological night (i.e., circadian misalignment)-a time when endogenous melatonin levels were still high indicating the internal circadian clock was still promoting sleep and related functions. We show the longer melatonin levels remained high after wake time, insulin sensitivity worsened. Overall, we find a simulated 5-day work week of 5-hr-per-night sleep opportunities and ad libitum food intake resulted in ∼20% reduced oral and intravenous insulin sensitivity in otherwise healthy men and women. Reduced insulin sensitivity was compensated by an increased insulin response to glucose, which may reflect an initial physiological adaptation to maintain normal blood sugar levels during sleep loss. Furthermore, we find that transitioning from the imposed short sleep schedule to 9-hr sleep opportunities for 3 days restored oral insulin sensitivity to baseline, but 5 days with 9-hr sleep opportunities was insufficient to restore intravenous insulin sensitivity to baseline. These findings indicate morning wakefulness and eating during the biological night is a novel mechanism by which short sleep duration contributes to metabolic dysregulation and suggests food intake during the biological night may contribute to other health problems associated with short sleep duration.
authors.affiliation: Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Eckel
authors.affiliation: Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, 80309, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Depner
authors.affiliation: Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
authors.forename: Leigh
authors.initials: L
authors.lastname: Perreault
authors.affiliation: Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, 80309, USA.
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Markwald
authors.affiliation: Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, 80309, USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Smith
authors.affiliation: Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, 80309, USA.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: McHill
authors.affiliation: Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
authors.forename: Janine
authors.initials: J
authors.lastname: Higgins
authors.affiliation: Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
authors.forename: Edward L
authors.initials: EL
authors.lastname: Melanson
authors.affiliation: Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder CO, 80309, USA. Electronic address: kenneth.wright@colorado.edu.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Wright
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000008:administration & dosage; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008550:Melatonin / Q000378:metabolism; D012890:Sleep / Q000502:physiology; D012892:Sleep Deprivation / Q000378:metabolism; D012893:Sleep Wake Disorders; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
chemical_list: D007328:Insulin; D005947:Glucose; D008550:Melatonin
keywords: sleep restriction