Study finds working “moderate” overtime may not have adverse effects on health and safety According to a February 2007 article in the Journal of Occupational and Environmental Medicine, a study of long work hours at a heavy manufacturer revealed that employees working “moderate” overtime (48 – 59 hours per week) were no more likely to incur adverse physical or mental health, presenteeism and disability outcomes. Those working 60+ hours were more likely to report new injuries and diagnoses, but those effects were overwhelmed by prior health, demographics and compensation categories. Many previous studies have suggested that long work hours generate a wide range of adverse outcomes across the employee continuum. This study found no evidence for pervasive effects working less than 60 hours per week.