Brain Function and Effects of Shift Work: Implications for Clinical Neuropharmacology

Abstract

Night or shift work is to a relevant extent unavoidable, suits a growing preference for flexibility and is predicted to spread. However, a significant percentage of shift workers report discomfort or health problems and they often (15–20% of cases) move to different occupations. Apart from social implications, the issue has medical and scientific relevance, with evidence suggesting that the circadian rhythm phases are neither equivalent nor interchangeable with respect to function and performance. Shift work may affect the gastrointestinal and cardiovascular functions, alter the hormonal and sleepiness cycles, favor sleep disturbances of medical relevance, interfere with behavior and social life and increase the risk of accidents (e.g. road accidents). The implications for clinical (neuro)pharmacology are relevant and, in several instances, critical. Shift work can interfere with mechanisms regulating drug kinetics in peripheral compartments and action at selective brain sites, either directly or through effects on the gastrointestinal/hormonal cycles. In this paper, the relevant literature is reviewed and original data on the effects of shift work are reported. Basic and clinical research should take into account the possible effects on drug action of an active life and working schedule in inappropriate phases of the circadian cycles and the risk of inadequate drug dosing or inexpected abnormal action in subjects under long-term or chronic treatment. A scientific approach, action by the scientific community involved in pharmacological research and monitoring by the regulating agencies are advisable. Regulation may help reduce the medical and social impact and improve quality of life.

Seafarer fatigue: a review of risk factors, consequences for seafarers’ health and safety and options for mitigation

“…Delaying sleep by 4 h for 3 consecutive days has led to a 6-fold reduction of the human blood transcriptome while the centrally mediated circadian rhythm of melatonin remains unaffected [81]. Fatigue from night and shift work alters the hormonal and sleepiness cycles and the lipid and glucose metabolism [82]. Despite signs indicating such possible disease mechanisms, however, compelling evidence remains to arise [83].…”

“…Fatigue favours sleeping disorders such as insomnia, and delayed or advanced sleep-phase disorders and interferes with behaviour and social life [68,82].…”

Shift Work and Correctional Officers: Effects and Strategies for Adjustment

“…The disruption of family life, personal activities, health problems, and burden of workload all contribute to reduced levels of morale, job satisfaction, and commitment, which, in turn, are related to sick days, absenteeism, and turnover (Koslowsky, 1991). Because of these adjustment problems, 15% to 20% of shift workers move to a day shift, and some may even change occupations (Costa, 1996;Garbarino et al, 2002).…”

Job characteristics in the United States Air Force and Mental health service utilization

“…Shift work is also a significant predictor of absenteeism for women (VandenHeuvel & Wooden, 1995). Shift work is associated with high accidents rates on and off work (Gabarino et al, 2002;Haermae & llmarinen, 1999). This may be related to the disturbances that shift work causes in circadian rhythms (Gabarino et al, 2002;Totterdell et al, 1995) and sleep quality (Marquie, Foret & Queinnec, 1999).…”

“…Shift work is associated with high accidents rates on and off work (Gabarino et al, 2002;Haermae & llmarinen, 1999). This may be related to the disturbances that shift work causes in circadian rhythms (Gabarino et al, 2002;Totterdell et al, 1995) and sleep quality (Marquie, Foret & Queinnec, 1999). Shiftwork can also have negative effects on marital quality and stability because it limits time with family (White & Keith, 1990).…”