Institute for Medical Psychology, University of Munich, Munich, Germany.
Curr Biol. 2012 May 22;22(10):939-43. doi: 10.1016/j.cub.2012.03.038. Epub 2012 May 10.
Obesity has reached crisis proportions in industrialized societies. Many factors converge to yield increased body mass index (BMI). Among these is sleep duration. 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). Social jetlag quantifies the discrepancy that often arises between circadian and social clocks, which results in chronic sleep loss. The circadian clock also regulates energy homeostasis, and its disruption-as with social jetlag-may contribute to weight-related pathologies. 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.
肥胖已在工业化社会达到危机临界点。诸多因素共同作用导致了体重指数（BMI）的增加。其中包括睡眠时间。生物钟通过同步过程来控制睡眠时机。睡眠时型描述了睡眠时机的个体差异，它由遗传背景、年龄、性别和环境（例如光照）决定。社会时差量化了生物钟与社交时钟之间经常出现的差异，这导致了慢性睡眠不足。生物钟还调节能量平衡，其紊乱（如社会时差）可能导致与体重相关的病理。在这里，我们报告了一项大规模流行病学研究的结果，表明除了睡眠时间外，社会时差与 BMI 的增加有关。我们的研究结果表明，“逆时而行”可能是肥胖流行的一个因素。这对于正在讨论的夏令时实施以及工作或上学时间的调整至关重要，这些都会影响个体累积的社会时差量。我们的数据表明，改善生物时钟和社交时钟之间的协调性将有助于肥胖的管理。
