BackgroundExcessive fatigue and insomnia are common among shift workers and can lead to negative effects such as reduced work performance, processing errors, accidents at work, absenteeism, reduced quality of life, and symptoms of depression. Moreover, work in rotating shifts can be a risk factor for different somatic and psychiatric diseases and may contribute to poor health, especially in elder adults and women. This review aims to show non-pharmacological preventive measures against fatigue and insomnia in shift workers.MethodComputerized literature searches in MedLine and in the Cochrane Library were performed with the following key words: shift work disorder, fatigue, insomnia, shift work, measures, treatment, therapy, strategies and coping. The search was limited to non-pharmacological studies that were conducted on human subjects and published as English-language articles in peer-reviewed journals since 1970. Additional studies were identified through the reference sections of relevant articles. Eighteen articles on fatigue in shift workers, including six original research articles with a total sample size of 3504 probands consisting of industrial workers, office employees, aircraft maintenance engineers, and non-shift workers working in simulated shifts, were analyzed, as well as seven articles on insomnia, including an original research article with a sample size of 26 media workers. Also, 4 reviews on shift work disorder were analyzed.MainThe occurrence of fatigue and insomnia in shift workers associated with a working period is described as shift work disorder. Estimations on the prevalence of shift work disorder in shift workers vary between 5 % and about 20 %; about one in three shift workers is affected by insomnia and up to 90 % of shift workers report regular fatigue and sleepiness at the workplace. We concluded that there is a necessity for treatments to improve the sleep quality of the shift working population. The most common non-pharmacological recommendations to improve sleep quality and to reduce insomnia and fatigue were scheduling, bright light exposure, napping, psychoeducation for sleep hygiene, and cognitive-behavioral measures.ConclusionSome important preventive coping strategies for fatigue associated with shift work such as napping and exposure to bright light have already been investigated and are generally approved. A few studies also provide good evidence for the efficacy of cognitive-behavioral techniques in the treatment of chronic primary and comorbid insomnia. These coping strategies summarized in this paper should be considered in the workplace health promotion programs of each work environment to improve working conditions for shift workers and to save money.

Based upon their in vitro receptor binding profiles, the atypical antipsychotics clozapine and olanzapine exhibit cholinergic receptor binding of similar potency. Data comparing the in vivo anticholinergic effects, however, of these neuroleptics upon neurocardiac control are sparse. The goal of this study was to compare the in vivo effects of clozapine and olanzapine upon neurocardiac control by assessment of the pulse rate variability (PRV) in schizophrenic patients and healthy controls. Twenty patients with schizophrenia (according to DSM-III-R criteria) treated with either clozapine (100-600 mg/day) or olanzapine (10-20 mg/day), and ten healthy controls, were recruited into the study. PRV was assessed by continuously recording the skin blood volume in the fingertip of the second digit under resting conditions and PRV parameters were calculated. When significant differences in PRV parameters between the patients and controls were detected by Kruskal-Wallis tests, Mann-Whitney tests were used to test for group differences between the olanzapine- and clozapine-treated patients. In comparison to the healthy controls, the PRV parameters of the clozapine- and olanzapine-treated schizophrenic patients were significantly reduced. Indeed the reduction of PRV was significantly greater in the clozapine-treated group compared to the olanzapine-treated group (P<0.05). Compared to the controls, only the clozapine-treated patients showed a significantly diminished low-frequency (LF)/high frequency (HF)-ratio, a PRV parameter reflecting sympatho-vagal balance. The significantly greater reductions in PRV parameters of the clozapine-treated compared to olanzapine-treated patients may be caused by clozapine's higher affinity for alpha(1)-adrenergic receptors in vivo compared with olanzapine. The similar LF/HF ratios of the healthy controls and olanzapine-treated patients suggests that the sympathetic-parasympathetic modulation of PRV remains relatively unchanged even during olanzapine treatment.

The functioning of the human body is regulated by the rhythmical change between rest and activity. The SCN (suprachiasmatic nucleus) is responsible for the central control of the biorhythm and the genetic prediction of the individual chronotype, whereas peripheral time cues such as light, social contacts and times of meals modulate the rhythmical activity of the body. Shift workers suffer from a disruption of the sleep-wake rhythm, insomnia and a lack of melatonin. These factors might trigger the development of breast cancer in female shift workers. The growing amount of data which indicate the high risk of breast cancer in female shift workers demonstrates the need for the implementation of prevention strategies against insomnia in shift workers. These strategies include regular sleep education courses on the prevention of sleep disorders in companies. The individual chronotype could be an important predictor for the adaptability to shift work.

The prevalence of clinical depression according to ICD-10 criteria in a selected clinical sample (referred to the sleep center) was 21.5 %. Mood scales tend to overestimate complaints as compared to psychiatric consultation. Interdisciplinary cooperation is recommended for both OSA patients with symptoms of depression and depressed patients with treatment resistance.