Life Wellbeing Waking an hour earlier reduces risk of serious depression: New study finds
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Waking an hour earlier reduces risk of serious depression: New study finds

People who are genetically predisposed to being night owls carry greater health risks. Photo: Getty
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It might sound counter-intuitive, but new research suggests waking up an hour earlier can help alleviate depression.

Not convinced? Let’s look to Donald Trump as an example.

When Mr Trump was US President, it was routinely reported that he watched TV into the early hours and didn’t seem to sleep much at all – and it was evident he wasn’t a happy person.

Can anyone recall when the man radiated joy?

So, was the lack of sleep making him depressed, or was depression causing him sleepless nights?

Short answer: They were feeding each other.

Certainly Trump’s disrupted sleep might go some way to explain his poor impulse control, cognitive oddities, volatile moods, elevated risk of suffering a heart attack, and pouchy skin.

So what’s the point of this story?

If you’re one of the many people who suffer disrupted or reduced sleep, researchers may have found a simple way to tamp down the risk of you turning into Donald Trump.

In a large new genetic study, scientists – from the Broad Institute of MIT and Harvard, and from the University of Colorado Boulder – conclude that waking up just one hour earlier “could reduce a person’s risk of major depression by 23 per cent”.

The study of 840,000 people didn’t focus on number of hours slept or lifestyle, but on the role of chronotype – which is a person’s propensity to sleep at a certain time.

The idea is that the setting of your interior sleep clock “influences depression risk”.

It’s one of the first studies “to quantify just how much, or little, change is required to influence mental health”.

Senior author Celine Vetter, assistant professor of integrative physiology at CU Boulder, in a prepared statement said: “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?

“We found that even one-hour earlier sleep timing is associated with significantly lower risk of depression.”

Genetics partly explain our sleep preferences

The researchers analysed data from a DNA testing company called 23andMe, and from the biomedical database UK Biobank.

Lead author Iyas Daghlas used a method called “Mendelian randomisation” that leverages genetic associations to help decipher cause and effect.

“Our genetics are set at birth so some of the biases that affect other kinds of epidemiological research tend not to affect genetic studies,” said Dr Daghlas, who graduated in May from Harvard Medical School.

According to Dr Daghlas, more than 340 common genetic variants, including variants in the so-called “clock gene” PER2, are known to influence a person’s chronotype, and genetics collectively explains 12 to 42 per cent of our sleep timing preference.

The researchers assessed genetic data on these variants from 850,000 individuals, including data from 85,000 who had worn wearable sleep trackers for seven days and 250,000 who had filled out sleep-preference questionnaires.

This gave the researchers “a more granular picture, down to the hour, of how variants in genes influence when we sleep and wake up”.

In the largest of these samples, about a third of subjects described themselves as morning people, 9 per cent were night owls and the rest were somewhere in the middle.

Overall, the average sleep mid-point was 3am, which means they went to bed at 11pm and got up at 6am.

With these insights in hand, the researchers turned to a different sample that included genetic information, medical and prescription records, and surveys about diagnoses of major depressive disorder – all of which was analysed using novel statistical techniques.

The results?

Bingo. The subjects with genetic variants that predisposed them to be early risers also had lower risk of depression.

This suggests that if someone who normally goes to bed at 1am goes to bed at midnight instead and sleeps the same duration, they could cut their risk by 23 per cent.

If they go to bed at 11pm, they could cut it by about 40 per cent.

Why is this so? One possibility is that people who get out of bed earlier are exposed to more sunlight, which serves to stabilise their circadian clocks.

But it’s unclear from the study if early risers could benefit from getting up earlier.

According to the authors, “for those in the intermediate range or evening range, shifting to an earlier bedtime would likely be helpful”.

The findings need to be confirmed by randomised clinical trial.

“But this study definitely shifts the weight of evidence toward supporting a causal effect of sleep timing on depression.”

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