Changing to Daylight Saving Time Cuts Into Sleep and Increases Workplace Injuries

According to a newly released paper in the Journal of Applied Psychology (2009, Vol. 94, No. 5, 1305–1317), switching to daylight saving time during the spring leads to both higher numbers of, and more severe, workplace injuries, likely because of cutbacks in sleep. The study has implications for both the appropriateness of this time shift practice, as well as for workplace safety policies.

The authors, Christopher M. Barnes and David T. Wagner of Michigan State University, examine the differential influence of time changes associated with Daylight Saving Time on sleep quantity and associated workplace injuries. In Study 1, the authors used a National Institute for Occupational Safety and Health database of mining injuries for the years 1983–2006, and they found that in comparison with other days, on Mondays directly following the switch to Daylight Saving Time—in which 1 hour is lost—workers sustain more workplace injuries and injuries of greater severity. In Study 2, the authors used a Bureau of Labor Statistics database of time use for the years 2003–2006, and they found indirect evidence for the mediating role of sleep in the Daylight Saving Time–injuries relationship, showing that on Mondays directly following the switch to Daylight Saving Time, workers sleep on average 40 min less than on other days. On Mondays directly following the switch to Standard Time— in which 1 hour is gained—there are no significant differences in sleep, injury quantity, or injury severity.

The article can be reviewed or downloaded at:  http://www.apa.org/journals/releases/apl9451317.pdf.