Are 'Night Owls' a Safety Hazard?

‘Night owls’ – those people who prefer to go to bed late and sleep in – have poorer attention, slower reactions, and increased sleepiness, according to a new international study.

The research found people whose internal body clock dictates later-than-usual sleep and wake times (approximately 2.30 am to 10.15 am) have lower resting brain connectivity in many of the regions linked to the maintenance of consciousness.

Lead researcher Dr Elise Facer-Childs said these cognitive disadvantages were most problematic when night owls were forced to work a standard 9-5 schedule.

“This mismatch between a person’s biological time and social time – which most of us have experienced in the form of shift work or jet lag – is a common issue for ‘night owls’ trying to follow a normal work day.”

“Our study is the first to show how the brain at rest could help to explain why ‘night owls’ may face cognitive disadvantages when being forced to fit into these constraints.”

According to the Australian Bureau of Statistics, approximately 60 percent of Australians work a standard 9-5 schedule, and the research suggests that up to 40 percent of these could be night owls.

The study, which was published in the journal SLEEP, studied 38 participants with MRI scans and continuous sleep/wake monitoring for two weeks.

Unsurprisingly, early risers were more alert and had their fastest reaction times during the morning, while night owls performed better in the evening. However, the night owls did not perform significantly better than the early risers.

“Interestingly, the brain connectivity in the regions that could predict better performance and lower sleepiness was significantly higher in the early risers at all time points, suggesting that the resting state brain connectivity of ‘night owls’ is impaired throughout the entire day (8am – 8pm).”

“As a society, if we could be more flexible about how we manage time it could go a long way towards maximising productivity and minimising health risks.”

The study involved coordinated research between the University of Birmingham, the University of Surrey, and the University of Campinas.