People whose sleep pattern defies their natural body clock are more likely to have depression and reduced wellbeing, new research has found.
A team of genetic scientists at the University of Exeter also published the most robust evidence to date that people who are genetically programmed to rise early are more protected against major depression.
The research, published in Molecular Psychiatry, suggests positive outcomes for natural early risers could be partly attributable to society’s nine-to-five working patterns.
An Irish expert in sleep psychology said people were becoming more aware of the benefits of regular sleep.
Prof Gary Donohoe at National University of Ireland, Galway (NUIG) pointed to the change in working habits brought about by the pandemic, and the difficulties expressed by hospitality employers in attracting people back to work unsociable shifts.
“For me as a clinician, it is not just because the hours are unsocial it is also because it is difficult to establish a sleep routine . . . It can really mess with your ability to get eight hours sleep,” he said.
“From a clinical perspective, what we know absolutely is that getting eight hours of sleep is one of the best projectors of physical and mental health. It is as important as exercise and good nutrition.”
Prof Donohoe noted that adults’ sleep patterns tend to gravitate towards early rising as they age. Teenagers and young adults find it more difficult to get out of bed in the morning, he said.
“The problem, in European settings anyway, is we often start schools between eight and nine in the morning,” he said. These early starts have more of an impact on young, growing people than people in their 30s-50s who have learned a routine over decades, he added.
Prof Donohoe, who is the founding director of NUIG’s Cognitive Genomics Research Centre, said people able to work from home during the past year may have found they could catch up on sleep during time normally reserved for their commute.
“When you have an opportunity to organise yourself according to your own body clock you are maximising your chance to get eight hours of sleep. There is that versus trying to fit a square peg in a round hole where you have to be in for a time that mightn’t necessarily suit you,” he added.
The Exeter research group used data on more than 450,000 European adults from the UK’s large-scale biomedical database to examine whether 351 genes linked to being an early riser were causally associated with seven mental health and wellbeing outcomes, including major depression. As well as genetic information, participants completed a questionnaire to determine if they were a morning or evening person.
Overall, the scientists found that morning people, or early-risers, were more likely to be aligned to their natural body clock.
When testing this theory on shift workers, the team found being a morning person was not necessarily protective for depression. Early birds may not have enhanced protection against poor mental health outcomes if doing shift work but the report notes this theory was inconclusive.
Senior author Dr Jessica Tyrrell, of the University of Exeter, said: “Our research indicates that aligning working schedules to an individual’s natural body clock may improve mental health and wellbeing in night owls.”