Night owls may be twice as likely to underperform at work than colleagues who prefer the morning, scientists say.
They are also at greater risk of falling into early retirement due to disability, according to the Finnish study.
Researchers assessed almost 6,000 workers in Finland who are part of a life-long project to see if night owls are less efficient than morning larks.
When the study participants were 46, they were quizzed about sleep patterns to establish their natural ‘chronotype’ – the point during the day they are most alert.
Night owls may be twice as likely to underperform at work than colleagues who prefer the morning, scientists say (file photo)
Overall, 10 per cent of men and 12 per cent of women were deemed to be evening chronotypes and the majority of these – 72 per cent – worked in day jobs.
The findings, published in the journal Occupational & Environmental Medicine, suggest that night owls may be twice as likely as morning larks to underperform at work.
Results were based according to their self-rated performance on a scale of 0-10, where anything less than a seven was judged an underperformance.
Around 28 per cent of men and 24 per cent of women classed as owls were considered as underperforming at work when they were 46, a significantly higher proportion than among larks or intermediate chronotypes.
The odds of underperformance were twice as high among the owls as they were among the larks.
Genes are the biggest factor in determining a person’s chronotype, but one’s surroundings such as daylight and social schedules is also influential.
The odds of underperformance were twice as high among the owls as they were among the larks (file photo)
The participants were also monitored over the next four years to see who had stopped working and taken a disability pension.
Night owls were also more likely to have retired early due to disability, though these numbers were small.
‘We found that evening chronotypes were associated with double-sized odds of poor work ability compared with morning chronotypes,’ the authors from the University of Oulu in Finland wrote.
They suggested that a person’s chronotype should be considered ‘when planning work schedules’.
Although the researchers observed a strong correlation between underperformance and taking a disability pension, they could not establish a causal relationship.