Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week (abbreviated as 24/7). The practice typically sees the day divided into “shifts”, set periods of time during which different groups of workers take up their posts. The term “shift work” includes both long-term night shifts and work schedules in which employees change or rotate shifts. In medicine and epidemiology, shift work is considered a risk factor for some health problems in some individuals, as disruption to circadian rhythms may increase the probability of developing cardiovascular disease, cognitive impairment, diabetes, and obesity. Shift work can also contribute to strain of marital, family, and personal relationships.