Summary: A study analyzing data from over 7,000 individuals over 30 years found that shift work in early adulthood are linked to poorer health outcomes, including reduced sleep quality and increased depressive symptoms, by age 50. Those with volatile work hours experienced negative health impacts, comparable to having less than a high school education. The study also highlights health inequities, with Black Americans and those in vulnerable social positions most affected.
Key Takeaways:
- The study used data from The National Longitudinal Survey of Youth-1979, involving more than 7,000 US participants, to explore the long-term health impacts of work schedule patterns over 30 years.
- Findings indicate that individuals with nonstandard work schedules—especially those transitioning to volatile hours after stable schedules in their 20s—faced worse health outcomes by age 50, including poor sleep quality and increased depressive symptoms.
- The research highlighted health disparities, showing that Black Americans and those with lower educational levels were more likely to experience the adverse health effects of volatile work schedules.
Nonstandard work schedules earlier in life may be associated with worse health, including worse sleep and more depressive symptoms, years later, according to a study published in PLOS ONE.
Studies have consistently shown that nonstandard work schedules—working outside the traditional nine-to-five workday—can negatively impact physical and mental health as well as social and family life. The current study uses a life-course approach to provide a longer-term perspective on how work schedule patterns throughout a person’s working life impact their health in middle age.
Longitudinal Study Insights
Study author Wen-Jui Han, PhD, from New York University used data from The National Longitudinal Survey of Youth-1979, which includes data on more than 7,000 people in the US over 30 years, to see whether employment patterns in younger adulthood were associated with sleep, physical health, and mental health at age 50.
Han found that around a quarter of participants (26%) worked stable standard hours, with a further third (35%) working mostly standard hours. 17% initially worked standard hours in their 20s, later transitioning into volatile working patterns—a combination of evening, night, and variable hours. 12% initially worked standard hours and then switched to variable hours. A final 10% were mostly not working over this period.
Health Impact of Work Patterns
Compared to individuals who mostly worked during traditional daytime hours throughout their working career, those whose careers featured more volatile work schedules slept less, had lower sleep quality, and were more likely to report depressive symptoms at age 50.
The most striking results were seen in those who had stable work hours in their 20s and then transitioned to more volatile work hours in their 30s. This effect size was significant and similar to that of being educated only to below high school level.
Racial and Gender Disparities
Han also found racial and gender-related trends. For example, Black Americans were more likely to have volatile work schedules associated with poorer health, highlighting how some groups may disproportionately shoulder the adverse consequences of such employment patterns.
Han suggests that volatile work schedules are associated with poor sleep, physical fatigue, and emotional exhaustion, which may make us vulnerable to an unhealthy life. The study also suggests that positive and negative impacts of work schedules on health can accumulate over one’s lifetime while highlighting how employment patterns can contribute to health inequities.
Societal Implications
“Work that is supposed to bring resources to help us sustain a decent life has now become a vulnerability to a healthy life due to the increasing precarity in our work arrangements in this increasingly unequal society,” says Han in a release. “People with vulnerable social positions (eg, females, Blacks, low-education) disproportionately shoulder these health consequences.”
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