Working unpaid overtime linked with high stress and burnout: IWH study

Overtime work has previously been linked to depression, anxiety, psychological distress and burnout. Prior research, however, has not distinguished between paid and unpaid overtime as having potentially differential impacts on workers. This study sought to investigate the relationship between unpaid overtime and mental health in Canada’s working population.

The researchers conducted two rounds of an online survey, administered to approximately 4,000 Canadian workers in 2016 and 2019. Participants were drawn from a pool of about 100,000 Canadians who agreed to participate in occasional surveys. Those selected for the study were employed full-time at an organization with six or more employees.

In the survey, participants were asked about the number of unpaid overtime hours they usually work in a week. The researchers grouped them into one of three categories: no unpaid overtime, one to five hours a week (defined as moderate unpaid overtime), and six hours or more a week (defined as excessive unpaid overtime). Participants were also asked about the number of total (paid or unpaid) hours they worked in a week, and the researchers grouped them into three categories: 30 to 44 hours, 45 to 48 hours, and 49 or more hours.

Participants were also asked about their mental health, in particular their self-reported symptoms of stress and burnout, as well as their experiences with four other work environment factors (shift work, job control, social support and job insecurity). Sociodemographic information including age, gender, education level, and occupational position (that is, managerial or non-managerial) was also collected as part of the survey. Stress and burnout scores were on a scale of 0 to 100 where higher scores reflect higher stress or greater burnout. Score of 75 and above were defined as having stress or burnout.

Among the sample, 49 per cent of respondents reported working no unpaid overtime, 31 per cent reported working moderate unpaid overtime, and 20 per cent reported working excessive unpaid overtime, that is, more than six hours a week. This study found that working unpaid overtime was associated with high levels of stress and burnout. Compared to those working no unpaid overtime:

• Men working excessive unpaid overtime were 85 per cent more likely to report stress and 84 per cent more likely to report burnout.
• Women working excessive unpaid overtime were 90 per cent more likely to report stress and 52 per cent more likely to report burnout.
• Women reporting moderate unpaid overtime were 68 per cent more likely to report stress and 31 per cent more likely to report burnout.

The strength of the association between unpaid overtime and poor mental health outcomes was comparable to that of shift work and low job control, which are widely accepted as work stressors.

This study shows that the more unpaid overtime hours worked, the more likely a worker is to report stress and burnout. Because of this, unpaid overtime may present a significant challenge to the mental health of workers and should be considered an occupational hazard similar to other broadly recognized stressors like shift work and low job control.

This study also suggests that unpaid overtime may have different impacts on a worker’s mental health than long work hours per se, as the number of hours of work were adjusted for as part of the analyses.

Data from the Canadian Labour Force Survey indicate that, in any given week, nearly one in ten employees will work some degree of unpaid overtime. From a policy standpoint, the study findings lend support to regulatory efforts to better safeguard workers from unpaid overtime and its associated health consequences.

This study is one of the first to look at the association of unpaid overtime with the mental health of workers. A strength of this study includes the survey that was used; it is one of the only Canadian surveys collecting information on both paid and unpaid overtime. Another unique feature of the survey is the inclusion of questions about other work-related stressors, such as shift work and low job control. This allowed the researchers to compare the strength of the association of unpaid overtime and mental health with these other well-known stressors.

Though the pool of survey participants from which the study sample was drawn is broadly representative of Canadians, a limitation is that the survey had a response rate of only 12 per cent. This may affect the representativeness of the sample.

A final limitation is that this study is cross-sectional in nature, giving a snapshot in time of mental health and overtime hours. This design does not allow the researchers to determine whether unpaid overtime leads to poor mental health outcomes, or if mental health struggles influence work hours—the results likely capture effects in both directions.