“We have known for some time that there is a relationship between sleep timing and mood, but a question we often hear from clinicians is: How much earlier do we need to shift people to see a benefit?” said researcher Celine Vetter. “We found that even one-hour earlier sleep timing is associated with a significantly lower risk of depression.”
How sleep impacts mental health
For the study, the researchers analyzed genetic data from over 850,000 participants. One portion of the group filled out questionnaires about their typical sleeping habits, while another portion wore wearable sleep trackers for one week. The team then combined that information with another dataset of survey responses about mental health and sleep records to determine if being genetically predisposed to waking up earlier impacted depression risk.
The large majority of the participants didn’t define themselves as either early risers or night owls, as the most common sleep patterns were from 11 p.m. to 6 a.m. However, the study also showed that participants that were genetically predisposed to waking up earlier were at a much lower risk for developing depression.
The researchers learned that putting more of an emphasis on sleep -- even by just one hour -- can have significant impacts. Going to bed at 12 a.m. versus at 1 a.m., while still waking up at 6 a.m., was linked with a 23% lower risk of depression; going to bed at 11 p.m. and maintaining a 6 a.m. wake-up time lowered the risk of depression by 40%.
The researchers also explained that the sleep midpoint -- the halfway point between sleeping and waking -- is an important factor in mental health. Consumers can lower their risk of depression by more than 20% with each hour earlier they make their sleep midpoint.
Getting on an earlier schedule
While sleeping can be tricky for many consumers, the researchers recommended some ways to go about adopting an earlier schedule and improving mental health.
“Keep your days bright and your nights dark,” said Vetter. “Have your morning coffee on the porch. Walk or ride your bike to work if you can, and dim those electronics in the evening.”