From The Ergoweb® Learning Center

Research Summary: The impact of overtime and long work hours on occupational injuries and illnesses: new evidence from the United States

Long Work Hours Means Higher Risk of Injury

Working extended or overtime hours was strongly associated with increased incidence of work related injury/illness according to a Dembe et al. analysis of 13 years of data collected by a national survey. Both the number of hours worked per week (over 40) and the number of hours worked per day (over 8) demonstrated a dose-response effect with risk of injury (per 100 worker-years).

The data for this study was derived from the National Longitudinal Survey of Youth, a sampling instrument first instituted in 1979 among 12,686 men and women to elicit general information about United States civilians between 14 and 22 years of age. Follow up interviews were done on a yearly basis through 1994, biannually since 1996. During each survey, subjects reported if they held a job over the prior year. Further details were obtained as to hours worked and the incidence of a work related injury.


The authors reviewed 110,236 job records collected between 1987 and 2000. Five exposure categories were defined: extended hours per week (jobs in which 60 or more hours per week was regularly spent working), extended hours per day (jobs in which 12 or more hours per day was regularly spent working), overtime (a yes response to a did you work overtime query), extended commute time (commuting regularly took 2 or more hours per day), and overtime or extended hours (a summary exposure variable). A work related injury/illness was the outcome of interest.


5,139 work related injuries/illnesses were reported during the study period with 2,799 occurring in jobs fitting one of the exposure categories. Jobs with:

This article originally appeared in The Ergonomics Report™ on 2006-01-24.