In a world divided into “morning larks” who wake up early, “night owls” who love to sleep in, and lots of people in-between, the early risers seem to enjoy the health advantage.
Evening types are less physically active and have a higher risk of dying sooner. Studies have found that “eveningness” may be a risk factor for mental and physical health, even in healthy young adults.
Now more research suggests it pays to rise earlier, especially when it comes to mental health, with a one-hour earlier wake time associated with a 23% lower risk of depression, according to a study published in JAMA Psychiatry.
It's easy for people to understand that sleep length can impact a person’s health, but most don’t realize sleep timing — when a person goes to bed or wakes up — could also be an important disease risk, said Iyas Daghlas, lead author of the study, a student at Harvard Medical School and research fellow at a lab studying the genetic bases of sleep and circadian rhythms.
Up to 40% of the preference to wake up at a certain time — known as sleep chronotype — is influenced by our genetics, but it’s still possible to change that routine, he noted.
“We think that evening people and likely the intermediate people would benefit from going a little bit towards morning preference,” Daghlas told TODAY.
“DNA is not destiny and so just because something is influenced by genetics, even if it's influenced to a large degree by genetics, does not mean that it's not modifiable.”
Why would wake-up time impact depression risk?
One theory is that society is generally designed for morning types. Work, school and business start early in the day, leaving evening types to exist in a perpetual state of misalignment between their biological clock and the societal clock.
Another theory has to do with light.
“It's possible that light has a protective effect on your risk of being depressed,” Daghlas said. “People who are early morning types tend to be out and about and are exposed to more light than evening types who will wake up later and stay up later.”
For the study, he and his colleagues analyzed data from almost 840,000 adults using Mendelian randomization, a genetics method that allowed the researchers to look at cause-and-effect relationships between risk factors and disease outcomes. It’s a way to emulate a clinical trial without actually conducting a trial, Daghlas said.
They found “robust genetic evidence” that preferring an earlier wake time had a protective association when it came to depression risk. The findings suggest the time when people go to bed and wake up is a risk factor for depression. It’s not clear from this study whether people who are already morning types could cut their depression risk more by waking up even earlier.
How to make waking up earlier easier:
Night owls and intermediate chronotypes may think their preference is irreversible, but that’s not necessarily the case, Daghlas said.
To help yourself go to sleep and wake up earlier, try adjusting these environmental factors:
Avoid blue light exposure from electronics at night: Lots of blue light in the evening plays a “huge role” in causing people to go to sleep later, Daghlas noted.
Make your bedroom very dark: The optimal setup is complete darkness, which is not always possible, but as much darkness as possible is very beneficial, he noted.
Get lots of sunlight in the morning: Daghlas recently moved from Massachusetts to California and even though he’s an evening person, it’s been easy to wake up in the morning because there’s lots of sunlight in his new home.
Stop drinking coffee earlier in the day: Caffeine can take a long time to be cleared from your system, so even drinking coffee at 3 p.m. can have an effect on the body at night. Minimizing afternoon intake can help you fall asleep faster at bedtime.
To figure out your sleep chronotype, try the Morningness–Eveningness Questionnaire.