VOA慢速英语:Change in Work Schedule Could Cure 'Social Jet Lag'

out of it – adj. idiomatic not thinking clearly. For example, “I’m so out of it this morning. I poured orange juice in my coffee instead of milk.”

jet lag – n. a tired and unpleasant feeling that you sometimes get when you travel by airplane to a place that is far away

circadian rhythm – n. physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism's environment. They are found in most living things, including animals, plants and many tiny microbes.

cycle – n. a set of events­ or actions that happen again and again in the same order : a repeating series of events or actions

shift – n. the scheduled period of time during which a person works