Shift workers are required to be awake and alert, often at times when the circadian clock is in its incompatible nighttime mode. The ensuing lack of alertness can spell danger—on the road, operating machinery, prescribing medications in the emergency room, and so on. Some people are more tolerant to shift work than others. A night owl, for example, will adjust more easily than a lark to the night shift. Switching across shifts, or alternating days off with shiftwork, presents a formidable challenge to the circadian timing system.
Research focuses on methods to expedite adjustment to the shifts—or at least partial adjustment that allows sufficient recovery sleep to maintain functionality. There is no magic bullet, however. We weren’t built for shift work—it is an artifice of the competitive post-industrial age, inherently dangerous to workers’ health.