Social jet¹ lag² refers to the feeling of being very tired when you return to work after a holiday, especially because of changes to your sleeping pattern.

Social jet lag指休假结束返回工作岗位时的倦怠感，主要是由睡眠模式的变化引起的，称为“假后返工时差”。

The root cause of social jet lag is the more relaxed sleeping pattern that many people adopt when on holiday. Conscious that they don't need to be up at the crack of dawn the next day, people luxuriate in the opportunity to lie in, getting up later in the morning and going to bed later in the evening. Faced with going back to work after perhaps as much as two weeks of a different cycle of waking and sleeping, a person's body clock is thrown out of sync. This has a similar effect to the one experienced³ by flying west across one or more time zones.

“假后返工时差”的根本原因是人们在休假期间往往享受一种比较放松的睡眠模式。因为知道第二天不用早起，人们就会充分享受赖床、晚睡和晚起的时光。在经历了一段时间完全不同的作息方式要回到工作状态之时，人们的生物钟已经完全不在休假前那个状态了。这种感觉就跟乘坐飞机从东半球跨越好几个时区飞到西半球的感觉一样，（是有时差的）。