Are you a morning or an evening person? If you’re a night owl you’re well equipped to be a shift worker, particularly night shifts.
If you’re not, research from Oxford University suggests you should be cautious about taking a job where you work through the night.
It seems some people have a genetic predisposition to being a night owl, and research led by Oxford University’s Leverhulme Centre for Demographic Science finds this protects regular night-shift workers against the health risks that result from sleeping less.
This is important stuff because up to a quarter of public-sector employees in the UK do some form of night work.
About the same numbers in other countries are shift workers.
But increasing evidence shows night work and persistent disruption of the body clock is a serious risk factor for health and may lead to conditions such as depression, heart disease and type 2 diabetes.
Using the UK Biobank database, the Oxford University researchers looked at 53,211 workers between 2006 and 2018 to investigate if they had a genetic propensity to “eveningness”.
Their study found night work is linked to significant sleep penalties, the greatest of which were in people who work constant nights.
According to the study: “This is given the fact sleep plays an essential role for physical and mental health”.
The researchers found, in general, people who work nights more frequently sleep less. Regular night-shift workers self-reported 13 minutes less sleep a night, compared to those who never worked through the night.
But the research also shows having this higher genetic propensity to “eveningness” has a strong protective effect, reducing the sleep penalty by up to nearly a third.
Dr Evelina Akimova, lead author, said: “What we found particularly exciting is that we were able to use multiple measures of eveningness including genetic, self-reported, and accelerometer measures to advance our knowledge of sleep penalties among night-shift workers.”
Professor Melinda Mills, lead senior author, added: “There are health implications for night-shift workers, but our study shows that these vary between individuals dependent on their chronotype, and that should be considered when designing interventions.”
These findings go a long way to explaining why some people can’t cope with night shifts while others thrive.