The problem: shiftwork.

Shiftwork, particularly that including night work, causes disruption of biological rhythms and perturbation of the social and family life that can negatively affect performance efficiency, health, and social relations. Adverse effects can manifest themselves in the short term as sleep disturbances, shiftlag syndrome, psychosomatic troubles, errors, and accidents; in the long term, there is an increased risk for gastrointestinal, psychoneurotic, and cardiovascular diseases, and women shiftworkers can be more vulnerable in relation to their reproductive function and family duties. A high interindividual variability is recorded in both short-term adjustment and long-term tolerance, being connected to individual factors as well as to work organization (shift schedules in particular) and social conditions.