People who like staying up late twice as likely to underperform at work compared to early birds, claims study
Morning chronotypes or 'larks' tend to do better early in the morning, evening-types or 'owls' later in the evening, while intermediate types have no strong preference, says the study
If you are a “night owl” and prefer staying up late at night, you could be at risk of underperforming at work. Researchers have found that such people were twice as likely to underperform at work as well as have an increased risk of early retirement due to disability, as compared to early birds or early risers.
“Evening chronotype is associated with poor work ability and disability pensions at midlife. In both sexes, the odds of poor work ability were double or more among evening-types as compared with morning-types even after taking account of potentially influential factors, such as sleep duration and working hours,” write authors from the University of Oulu in their analysis. The findings have been published in the journal Occupational & Environmental Medicine.
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According to experts, "chronotype" can be described as an individual’s preference for timing of sleep and activities. The inner clock influences the cycles of sleep, activity, eating, body temperature and hormone excretion in an approximately 24-hour period.
Morning chronotypes or "larks" tend to do better early in the morning, evening-types or "owls" later in the evening, while intermediate types have no strong preference. While chronotype is largely genetic, environmental factors such as exposure to daylight, work schedules and family life can also influence it.
“Owls don’t usually fall asleep early enough to get the recommended 7-plus hours of sleep on standard working days, leading to sleep debt and catch-up sleep on non-workdays, known as social jet lag. This mismatch has been linked to health problems, while long-term sleep deprivation is linked to poorer overall health and cognitive performance, potentially hampering productivity at work, say the researchers,” says the team.
To explore this further and find out if chronotype may also be linked to early retirement on health grounds, the authors drew on data from the Northern Finland Birth Cohort 1966 Study. The aim was to evaluate whether evening chronotypes have poorer work ability and a higher probability for early disability pensions than morning types in middle age.
When the participants turned 46, they were questioned about their working life and health, as well as about their sleep patterns to determine their natural chronotype. Participants rated their own performance at work on a scale of 0-10 using a validated scoring system. Their data were linked to national registries for social security and pension payments.
A total of 2,672 men and 3,159 women, all of whom were working in 2012 and for whom full details were available, were included in the final analysis. They were monitored over the next four years to see who had stopped working and taken a disability pension. An estimated 84 people received a new disability pension during this period, 17 people died, three of whom had taken a disability pension.
The proportions of those who were "larks" or early risers, intermediate chronotype, and "owls" were 46%, 44% and 10% among the men, and 44%, 44% and 12% respectively among the women.
An estimated 1 in 4 of the men (28%) and women (24%) classified as owls were underperforming at work when they were 46, a significantly higher proportion than among larks or intermediate chronotypes. “Compared with larks, owls had worse ratings for every variable related to sleep and health. Owls more often reported short sleep duration, insomnia, and high levels of social jet lag. And they were also more likely to be unmarried and out of work,” says the report.
During the four-year monitoring period, underperformance was strongly linked to a greater risk of taking a disability pension for both sexes, with male owls three times as likely to take a disability pension as male larks, although the impact of chronotype was significantly weakened when sleep patterns and working times were taken into account.
The research team cautions that this is an observational study, and therefore, cannot establish the cause. However, they recommend that chronotype be taken into account in supporting work performance, both in individual-level health promotion and organizational-level planning of work schedules.
“Eveningness appears a previously unrecognized risk factor for poor work ability and early disability. We suggest that individual chronotypes be considered in attempts to lengthen work careers," the report states.
"Especially with evening-types, the importance of a healthy lifestyle, sleep and suitable working times should be remembered. Actions matching the internal and social rhythm, targeted to either the individual, the environment or both, could help to support careers of evening-types,” the authors conclude.