Night Owls 70% More Likely To Leave Workforce Early, Study Finds

Study Ties Night Owls to Earlier Workforce Exits, Though It Cannot Show Why

Night owls exit the workforce early about 70% more often than early risers. In a Finnish study of more than 5,600 people followed from age 46 to 57, night owls were granted disability pensions at that higher rate, and the pattern held in both men and women after researchers accounted for education, occupation, and income.

Disability pensions in Finland go to workers whose health problems sharply reduce their long-term ability to work even after treatment and rehabilitation. Each one requires a physician’s certificate, and pensions can be full or part-time, temporary or permanent. They are not handed out to people for disliking early mornings.

Published in Occupational and Environmental Medicine, the results show an association but cannot establish that a late body clock causes early exits from work. Authors also say the gap poses a serious problem for national economies, since it appears during the core years of a career.

Roughly 10% of Men and 12% of Women Were Night Owls

Participants came from the Northern Finland Birth Cohort 1966, a long-running project that follows people born that year in the country’s two northernmost provinces. In 2012, at age 46, members answered six survey questions covering topics such as how easily they woke up, how tired they felt in the first half hour of the day, and whether they considered themselves morning or evening people. Their scores sorted them into morning types, in-between types, or evening types, the researchers’ label for night owls. That trait, called chronotype, is a person’s natural lean toward early or late sleeping and alertness, and genes heavily influence it.

Researchers analyzed 5,679 participants, 2,597 men and 3,082 women, who had not retired or previously received a disability pension. Men and women were analyzed separately. About 10% of men and 12% of women were evening types, while morning types and in-between types each made up more than 40% of both groups.

To check that the survey captured a biological trait, researchers also compared answers with genetic scores for morningness, collected when participants were 31. The two were modestly linked, which gave the survey some biological backing. Researchers then tracked government pension records through the end of 2023.

Evening Types Were Granted Disability Pensions at Higher Rates

By the end of follow-up, 135 men (5.2%) and 249 women (8.1%) had been granted a first disability pension. Among evening types, the shares reached 8.3% of men and 12.1% of women, compared with 5.0% and 7.2% among morning types.

An earlier study of the same group found that evening types at 46 had twice the odds of rating their own ability to work as poor. It also found a higher pension rate in men, but not in women, over just four years, when pension numbers were low. The 12-year follow-up showed the gap in both sexes.

Accounting for Health and Work Hours Shrank the Night Owl Gap

Evening types entered the study with poorer health. Nearly half of evening-type men (49.4%) and 43.5% of evening-type women rated their health as poor, compared with 28.1% and 25.0% of their morning-type counterparts. They also reported less physical activity, more insomnia, and more social jetlag, meaning a bigger difference between sleep timing on workdays and days off. Evening types were less likely to be married or living with a partner and more likely to be unemployed, although they were more educated.

More than 70% of evening types who reported their schedules worked standard day jobs, yet night shifts were more common among them, at about 19% of evening-type men versus 6% of morning-type men. Researchers note that a typical Finnish workday starts around 8 a.m., an hour when evening types may function below their best.

When researchers factored in health and health habits, the gap shrank enough that it could no longer be clearly told apart from chance in either sex. Working-time factors, including weekly hours and whether people worked days, evenings, or nights, produced the biggest drop, cutting the gap from about 70% to about 40% in men and under 20% in women. With everything factored in at once, the gap nearly vanished.

Authors caution against reading that last result as a sign the risk disappears. Some of those factors, poor health among them, could be steps on the path from a late body clock to a pension instead of separate influences, so the final model may have overcorrected. They believe poorer health is the main contributor, since a pension cannot be granted without documented long-term decline.

Why education and income did not shrink the gap is unclear, though the authors float one idea: poor sleep or declining mental health can dull thinking skills, and demanding professional jobs lean heavily on them.

Night owls make up a sizable share of the population, the authors note, and this study cannot say whether rigid work schedules are to blame. A gap this large in early workforce exits, seen in both men and women, makes it fair to ask whether conventional work hours suit everyone equally well.

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Disclaimer: This article is based on one observational study and is not medical advice. Readers with concerns about sleep or health should consult a qualified professional.

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