Institutional members access full text with Ovid®

Share this article on:

Sleep, Fatigue, Recovery, and Depression After Change in Work Time Control: A One-year Follow-Up Study

Takahashi, Masaya PhD; Iwasaki, Kenji PhD; Sasaki, Takeshi MSc; Kubo, Tomohide PhD; Mori, Ippei PhD; Otsuka, Yasumasa PhD

Journal of Occupational and Environmental Medicine: September 2012 - Volume 54 - Issue 9 - p 1078–1085
doi: 10.1097/JOM.0b013e31826230b7
Original Articles

Objective: We examined how change in work time control was associated with sleep and health 1 year later.

Methods: Work time control, sleep, fatigue, recovery, and depression were assessed at baseline (T1) and at follow-up (T2) for 2382 daytime workers. The change in work time control from T1 to T2 was classified into four groups: low to low, low to high, high to low, and high to high.

Results: A repeated-measures analysis of covariance showed significant decreases in the frequency of insomnia symptoms and depressive symptoms from T1 to T2 for the low to high group, which were similar to the high to high group. Significantly lower fatigue was found for these two groups at T2.

Conclusion: An increase in work time control, in addition to its stable high level, may produce beneficial effects upon sleep and health.

From the National Institute of Occupational Safety and Health (Drs Takahashi, Iwasaki, and Kubo, and Mr Sasaki), Nagao, Tama-ku, Kawasaki, Japan; The Institute for Science of Labour (Dr Mori), Sugao, Miyamae-ku, Kawasaki, Japan; and Department of Psychology (Dr Otsuka), Hiroshima University Graduate School of Education, Kagamiyama, Higashi-Hiroshima, Japan.

Address correspondence to: Masaya Takahashi, PhD, National Institute of Occupational Safety and Health, 6-21-1, Nagao, Tama-ku, Kawasaki 214-8585, Japan (

Disclosure of funding received for this work: National Institute of Occupational Safety and Health, Japan (JNIOSH).

Disclosure: Authors Takahashi, Iwasaki, Sasaki, Kubo, Mori, and Otsuka have no relationships/conditions/circumstances that present potential conflict of interest

The JOEM Editorial Board and planners have no financial information related to this research.

Copyright © 2012 by the American College of Occupational and Environmental Medicine