Night owls have a greater risk of dying sooner than morning people, according to a new study from Northwestern Medicine in Chicago and the University of Surrey in the U.K. The findings also show that night owls tend to have higher rates of diabetes, psychological disorders and neurological disorders.
The research, based on nearly half a million participants in the UK Biobank Study, found that night owls — those who like to stay up late into the night and have a hard time getting out of bed in the morning — have a 10 percent higher risk of dying than morning people.
The results held true after scientists adjusted for the expected health problems in owls.
“Night owls trying to live in a morning lark world may have health consequences for their bodies,” said co-lead author Dr. Kristen Knutson, associate professor of neurology at Northwestern University Feinberg School of Medicine.
“It could be that people who are up late have an internal biological clock that doesn’t match their external environment,” Knutson said. “It could be psychological stress, eating at the wrong time for their body, not exercising enough, not sleeping enough, being awake at night by yourself, maybe drug or alcohol use. There are a whole variety of unhealthy behaviors related to being up late in the dark by yourself.”
Previous research in this field has focused on the higher rates of metabolic dysfunction and cardiovascular disease, but this study is the first to investigate mortality risk. The findings are published in the journal Chronobiology International.
“This is a public health issue that can no longer be ignored,” said Dr. Malcolm von Schantz, a professor of chronobiology at the University of Surrey. “We should discuss allowing evening types to start and finish work later, where practical. And we need more research about how we can help evening types cope with the higher effort of keeping their body clock in synchrony with sun time.”
For the study, the researchers examined the link between an individual’s natural inclination toward mornings or evenings and their risk of mortality. They asked 433,268 participants, aged 38 to 73 years, if they are a “definite morning type” a “moderate morning type” a “moderate evening type” or a “definite evening type.” Deaths in the sample were tracked up to six and half years later.
The researchers also found that night owls had higher rates of diabetes, psychological disorders and neurological disorders.
Genetics and environment play about equal roles in determining whether a person is a morning or a night type, or somewhere in between, but nothing is set in stone.
“You’re not doomed,” Knutson said. “Part of it you don’t have any control over and part of it you might.”
According to Knutson, the following may help:
- make sure you are exposed to light early in the morning but not at night;
- try to keep a regular bedtime and don’t let yourself drift to later bedtimes;
- be regimented about adopting healthy lifestyle behaviors and recognize the timing of when you sleep;
- and do things earlier and be less of an evening person as much as you can.
“If we can recognize these chronotypes are, in part, genetically determined and not just a character flaw, jobs and work hours could have more flexibility for owls,” Knutson said. “They shouldn’t be forced to get up for an 8 a.m. shift. Make work shifts match peoples’ chronotypes. Some people may be better suited to night shifts.”
In the future, the researchers want to test an intervention with night owls to help them shift their body clocks to adapt to an earlier schedule. “Then we’ll see if we get improvements in blood pressure and overall health,” she said.
The switch to daylight savings or summer time is already known to be much more difficult for evening types than for morning types.
“There are already reports of higher incidence of heart attacks following the switch to summer time,” says von Schantz. “And we have to remember that even a small additional risk is multiplied by more than 1.3 billion people who experience this shift every year. I think we need to seriously consider whether the suggested benefits outweigh these risks.”
Source: Northwestern University