Working outside of the usual 9-to-5 schedule might not be the best for people’s health, especially for young adults, according to new research.

In a study featured in the journal PLOS ONE, New York University researcher Wen-Jui Han sought to understand how nonstandard work schedules, or working outside the regular 9-to-5 workday, can negatively affect the health and well-being of workers.

Using a life-course approach, Han was able to gain longer-term insights into how work schedule patterns throughout an individual’s working life impact their health, particularly when they reach middle age.

For her research, Han went over data from more than 7,000 people in the United States over 30 years old. This allowed her to see whether work patterns among younger adults can influence their sleep, physical health, and mental health when they reach age 50.

The results showed different work schedules for participants:

• 26% worked stable standard hours

• 35% worked mostly standard hours

• 17% started out working standard hours during their 20s but later transitioned to volatile work schedules (a combination of evening, night, and variable hours)

• 12% initially worked standard hours then transitioned to variable hours

• 10% mostly did not work over the period

Health effects of volatile work patterns

Participants who had volatile work patterns were found to have slept less and had lower sleep quality compared to those who mostly worked the usual daytime hours through their career. Those with volatile work schedules were also more likely to experience depressive symptoms by the time they reach age 50.

Han found the most striking results among participants who worked stable hours at age 20 but then switched to more volatile work hours at age 30. This showed a more significant effect, which can be compared to those of people who only reached below high school level in their education.

In terms of race and gender-related trends, the study showed that Black Americans with volatile work patterns suffered more from poorer health compared to their peers. This highlights how some people may disproportionately bear the brunt of these negative effects for having worked volatile hours.

For Han, volatile work schedules are linked to poor sleep, physical fatigue, and emotional exhaustion. These effects can make people more susceptible to an unhealthy life.

The findings show that the positive and negative effects of work schedules on people’s health can accumulate over their lifetime. They also suggest that work patterns can contribute to health issues in workers.

“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,” Han said.

“People with vulnerable social positions (e.g., females, Blacks, low-education) disproportionately shoulder these health consequences.”