Short Sleeping Time and Job Stress in Japanese White-Collar Workers

The aim of this study was to clarify the association between sleeping time and job stress in male Japanese workers. Male workers at one manufacturing plant were surveyed about job stress and sleeping time using a selfcompleted questionnaire. A total of 274 white-collar daytime workers were analyzed. Job stress factors and stress response were assessed using the Job Stress Questionnaire. Sleeping time on working days was divided into ≤ 5 h, 6 h, 7 h, and ≥ 8 h, and associations between job stress factors and stress response were analyzed. Shorter sleeping time was related to overtime work; about a quarter of those with sleep of ≤ 5 h worked more than 15 h overtime per week. Workers with shorter sleeping time, particularly those with ≤ 5 h sleeping time, were more likely to have job stress factors of quantitative workload and interpersonal conflict as well as psychological stress responses, such as anger, fatigue, tension/anxiety, and depressive symptoms. With shorter sleep, in subjects ≤ 39 years, scores of activity and fatigue decreased or increased respectively, whereas in those ≥ 40 years, scores for tension/anxiety and depressive symptoms increased. Shorter sleeping time was related to overtime work and increased job stress in male white-collar workers. Depression symptoms may be more closely associated with shorter sleeping times in workers aged ≥ 40. Adequate sleep duration is important for maintaining mental health.