[Sleep problems in occupational health].

It is important for workers to maintain a high quality of sleep to obtain their best performance at the workplace and in daily life. Insufficient sleep and/or dyssynchrony between internal clock and external light/dark cycles cause daytime sleepiness, and could result in a reduction of the working efficiency. Sleepiness may sometimes cause enormous economic and social losses. A recent report also indicated that lack of sleep might be a risk factor for chronic health problems such as metabolic syndrome. Therefore, it is important for an occupational physician to investigate and understand the sleep problems in workers, both to prevent serious accidents or loss at the workplace and to keep workers in good health.Additionally, the proper treatment of workers with some common sleep disorders such as an obstructive sleep apnea syndrome, or a circadian rhythm sleep disorder, needs to be understood. Shift work type is important for both worker's health and work management.