Millions of people all over the world either work a permanent night shift or rotate on a regular basis in and out of night shifts. This includes factory workers, truck drivers, police, and other emergency services personnel.

Hazards of this type of work schedule include fatigue, on-the-job sleepiness, restlessness, and decreased attention. All of these contribute to a decrease in safety for the workers themselves and those around them.

Psychologists are beginning to better understand the roots of such problems. One such cause is a “circadian misalignment” that pits the body’s natural tendency to relax and chill out after dark and be active in the morning against the need to stay awake and alert during the night and to sleep during the day. This can lead to additional problems for the individuals such as sleep disorders and poor physical health outcomes like heart problems and diabetes.

However, psychologists are now beginning to consult with police and medical workers to help them design more healthy rostering systems for their personnel. For more information on this research, see Violanti, Vila et al. in Policing, the New England Journal of Medicine (Vol 352, No. 2), and/or the American Journal of Surgery (Vol. 195, No.2).