Circadian Misalignment Augments Markers of Insulin Resistance and Inflammation, Independently of Sleep Loss

  1. Eve Van Cauter1
  1. 1Sleep Metabolism and Health Center, Department of Medicine, University of Chicago, Chicago, IL
  2. 2Neuropsychology and Functional Neuroimaging Research Unit at the Center for Research in Cognition and Neurosciences and the Université Libre de Bruxelles Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
  3. 3Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
  1. Corresponding author: Rachel Leproult, rleproult{at}gmail.com.

Abstract

Shift workers, who are exposed to irregular sleep schedules resulting in sleep deprivation and misalignment of circadian rhythms, have an increased risk of diabetes relative to day workers. In healthy adults, sleep restriction without circadian misalignment promotes insulin resistance. To determine whether the misalignment of circadian rhythms that typically occurs in shift work involves intrinsic adverse metabolic effects independently of sleep loss, a parallel group design was used to study 26 healthy adults. Both interventions involved 3 inpatient days with 10-h bedtimes, followed by 8 inpatient days of sleep restriction to 5 h with fixed nocturnal bedtimes (circadian alignment) or with bedtimes delayed by 8.5 h on 4 of the 8 days (circadian misalignment). Daily total sleep time (SD) during the intervention was nearly identical in the aligned and misaligned conditions (4 h 48 min [5 min] vs. 4 h 45 min [6 min]). In both groups, insulin sensitivity (SI) significantly decreased after sleep restriction, without a compensatory increase in insulin secretion, and inflammation increased. In male participants exposed to circadian misalignment, the reduction in SI and the increase in inflammation both doubled compared with those who maintained regular nocturnal bedtimes. Circadian misalignment that occurs in shift work may increase diabetes risk and inflammation, independently of sleep loss.

Footnotes

  • Received October 8, 2013.
  • Accepted January 6, 2014.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.

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  1. Diabetes vol. 63 no. 6 1860-1869
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