Night owls have higher mortality, study says
Evening types have a 10 per cent higher risk of dying than those up and at ’em in the morning, according to a new study from Northwestern Medicine in the U.S. and Britain’s University of Surrey.
“This is the first study, to our knowledge, that was able to look at mortality risk,” said Kristen Knutson, an associate professor of neurology and a sleep researcher at Northwestern.
Night owls have a harder time switching to daylight saving time and are more likely to suffer from diabetes and psychological and neurological disorders, she said.
Researchers surveyed 433,268 participants, ages 38 to 73, in the U.K., asking whether they considered themselves a “definite morning type,” “moderate morning type,” “moderate evening type” or “definite evening type.” Then researchers tracked deaths within the sample.
The study, published this month in the journal Chronobiology International, found that the 50,000 people who identified as definite night owls were more likely to die in the 6 1/2 years researchers followed them.
“It’s really important to get the message out to the night owls that there might be health consequences, and they should make an effort to be vigilant,” Knutson said.
She said the problem is living in a society with schedules that don’t welcome this — for example, being forced to get up earlier than your body clock prefers, “and then going back to night owl times on your days off or weekend. This jumping around the clock … is what really could lead to health problems.”
She suggests limiting evening activities and going to bed earlier, gradually.
She noted results are based on a single survey question, so researchers do not know exactly when participants went to sleep or how often sleep schedules were jumping around.
She and co-author Malcolm von Schantz, a University of Surrey professor who also researches sleep and circadian rhythms, note the increased likelihood of death could be the result of many factors, including behaviours that can potentially accompany late nights — eating at irregular times, not exercising or sleeping enough, or using drugs and alcohol.