Work schedules in the U.S. have become more varied where flexible work schedules and shift work for full time wage workers have increased dramatically in the last 20–30 years. In 2014, according to the U.S. American Time Use Survey (ATUS) approximately 9% of the employed population in the U.S. worked in multiple jobs during a one week period (MJHs). MJHs are more likely to work long hours and in nonstandard work schedules around the clock (24/7), factors known to impact sleep duration and quality and increase the risk of injury and other health outcomes.
Using activity diary data from the Bureau of Labour Statistics U.S. ATUS pooled over a nine-year period (2003–2011) we compared sleep duration in the 24 hour diary period between MJHs with single job holders (SJHs) using multivariate regression controlling for other work schedule and demographic factors.
Working long hours, beginning work early in the morning, and participating in work at night significantly reduced sleep duration. After controlling for these factors and other sleep-related factors (e.g. age, occupation), we found that males working more than one job on the diary day still had 0.37 hours less sleep (p < .05) on a weekday and 0.64 hours less sleep (p < .05) on a weekend day compared to male SJHs. Work at night had the greatest impact on sleep duration for females, reducing sleep time by almost an hour compared with females who did not work at night.
Workers with multiple jobs sleep significantly less than SJHs and are more likely to end up chronically sleep deprived which is known to result in errors or accidents in addition to other adverse health consequences. We also hypothesise that the high fragmentation of non-leisure activities throughout the day and between jobs may have an additional impact on the duration of sleep for MJHs.