Everyone sleeps differently and when someone goes to bed and wakes the next day is mostly based on their circadian rhythm, an internal clock that signifies it’s ready for sleep. An individual’s own work and family obligations can have an influence on this too. Pending when one goes to bed, the likelihood of them experiencing depression can be increased or decreased.
Multiple studies have shown that people who stay awake late during the night are twice as likely to experience depression when compared to those who wake early in the day. Mood disorders also have a great effect on one’s sleep patterns and due to this, it’s difficult to pinpoint the deciding factor on someone’s sleep quality.
A recent study conducted by the University of Colorado Boulder, the Broad Institute of MIT, and Harvard looked at 840,000 people and their sleep habits and the likelihood they would report feelings of depression. Researchers looked at the genetic responses from the popular DNA testing service, 23&Me, as there are more than 340 common genetic variants including variants in the PER2 gene, otherwise known as the “clock gene”, which is known to influence a person’s chronotype, explaining 12-42% of our sleeping preference. In addition, 85,000 of this group wore sleep trackers for 7 days and 250,000 completed sleep related questionnaires.
Results showed that about 9% of participants were night owls, about one third of all participants were early risers, and the rest were somewhere in between. The average sleep midpoint was 3am, meaning they went to bed at 11pm and woke at 6am. The question was then posed: “do those with genetic variants with a predisposition for them to be early risers have a lower risk of depression?” The answer was a very strong yes. Each one hour earlier sleep midpoint corresponded with a 23% lower risk of major depressive disorder.
What this means is that for someone who usually goes to bed at 1am, if they brought their sleep start time back one hour and maintained their overall total amount of sleep, they could cut their risk by 23%. If they moved it back another hour, this jumps up to a 40% risk cut. It’s unclear if this can be applied to those who already wake early but it could be beneficial. Possible explanations for this is an increased about of daylight being experienced or longer time spent with others while awake.
The take away message from the study is simple: keep your days bright and your nights dark.
Source: https://www.sciencedaily.com/releases/2021/05/210528114107.htm
