The first time I've heard about social jetlag - and possibly a factor in obesity (and likely other issues)
Social Jetlag and Obesity
- 1 Institute for Medical Psychology, University of Munich, Goethestrasse 31, 80366 Munich, Germany
- 2 Department of Molecular Chronobiology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
- Received 25 October 2011. Revised 27 January 2012. Accepted 20 March 2012. Available online 10 May 2012. Published online: May 10, 2012.
Obesity has reached crisis proportions in industrialized societies . Many factors converge to yield increased body mass index (BMI). Among these is sleep duration [ , , , , , , ,  and ]. The circadian clock controls sleep timing through the process of entrainment. Chronotype describes individual differences in sleep timing, and it is determined by genetic background, age, sex, and environment (e.g., light exposure) [ , ,  and ]. Social jetlag quantifies the discrepancy that often arises between circadian and social clocks, which results in chronic sleep loss [  and ]. The circadian clock also regulates energy homeostasis , and its disruption—as with social jetlag—may contribute to weight-related pathologies [ ,  and ]. Here, we report the results from a large-scale epidemiological study, showing that, beyond sleep duration, social jetlag is associated with increased BMI. Our results demonstrate that living “against the clock” may be a factor contributing to the epidemic of obesity. This is of key importance in pending discussions on the implementation of Daylight Saving Time and on work or school times, which all contribute to the amount of social jetlag accrued by an individual. Our data suggest that improving the correspondence between biological and social clocks will contribute to the management of obesity.
► In 70% of the population, biological and social clocks differ by >1 hr (social jetlag) ► Social jetlag is a predictor of BMI, especially for overweight individuals ► The decrease of sleep duration over the past decade concerns only workdays ► Individuals are progressively exposed to decreasing light, and their chronotypes delay