Keeping it Safe for Daylight Saving Time

Topic: Health & Safety
Publication: Journal of Applied Psychology (SEP 2009)
Article: Changing to Daylight Saving Time cuts into sleep and increases workplace injuries
Authors: C.M. Barnes & D.T. Wagner
Reviewed By: Benjamin Granger

Although Daylight Saving Time was originally proposed to align the human sleep/wake cycle with the Earth’s rotation cycle (and to give us more day light to BBQ on those warm summer afternoons!), Barnes and Wagner wondered if these time changes have detrimental effects on human sleep patterns and workplace injuries.

Using archival data, Barnes and Wagner discovered that the change from standard to Daylight Saving Time leads employees to get an average of 40 minutes less sleep on the night of the switch. They also found that the frequency and severity of workplace injuries increases on the Monday immediately following the switch to Daylight Saving Time. These trends provide evidence that reduced sleep is a likely explanation for the increased frequency and severity of workplace injuries following the time change in the spring.  On the other hand, no substantial effects on sleep and injury frequency or severity were found for the change back to standard time in the fall.

Although these findings are disconcerting, Daylight Saving Time is predictable and can be planned for long in advance. For example, this knowledge may encourage employees to “hit the sack” an hour early to prepare for the change in schedule. Organizations and managers can avoid scheduling particularly dangerous tasks on the Monday after the spring Daylight Saving Time switch (schedule them later in the week). Mangers may even schedule additional safety monitors on this day to help prevent injuries. By identifying this particularly dangerous work-day, organizations can protect their employees from injuries and themselves from lawsuits and other injury-related expenses.

Barnes, C.M. & Wagner, D.T. (2009). Changing to daylight savings time cuts into sleep
and increases workplace injuries. Journal of Applied Psychology, 94(5), 1305-1317.