Waking up just an hour early can reduce the risk of major depression, studies show.

Waking up just an hour early could reduce the risk of major depression by 23%, suggesting a radical new genetic study published in the journal on May 26. JAMA Psychiatry..

A study of 840,000 researchers from the University of Colorado at Boulder and MIT and Harvard University represents some of the strongest evidence that chronotypes (the tendency to sleep at specific times) affect the risk of depression. I will.

Also, quantifying the amount of change needed to affect mental health is one of the first studies.

After the pandemic, as people emerge from remote work and school, many tend to move to slower sleep schedules, but the findings can be significant.

We’ve known for some time that sleep timing and mood are related, but a common question asked by clinicians is how quickly people need to shift to benefit.Sleep timing is associated with a significantly reduced risk of depression.. “

Celine Wetter, University of Colorado, Boulder, Principal Investigator and Associate Professor of Integrated Physiology

Previous observational studies have shown that staying up late is more likely to suffer from depression twice as much as getting up early, regardless of how long you sleep. However, researchers have had difficulty deciphering what is causing what, as mood disorders themselves can disrupt sleep patterns.

Other studies have considered environmental factors that may affect both sleep timing and mood and confuse results, whether the sample size is small, relying on questionnaires from a single point in time. I didn’t.

In 2018, Better published a large long-term study of 32,000 nurses, showing that “early rising” is up to 27% less likely to develop depression in four years. I asked a question. A person who gets up early?

To better understand whether faster sleep is really protective and how much shift is needed, lead authors Iyas Daghlas, MD, have DNA testing companies 23 and Me and a biomedical database. We turned to data from UK Biobank. Daghlas then used a method called “Mendelia Randomization”. This helps to decipher the cause and effect by leveraging genetic associations.

“Because our genetics are set at birth, some of the biases that affect other types of epidemiological studies tend not to affect genetics studies,” Harvard Medical School said in May. Douglas, who graduated, said.

Over 340 common genetic variants, including so-called “clock gene” PER2 variants, are known to affect human chronotypes, and genetics is our sleep timing preference 12 ~ 42% are explained together.

The researchers evaluated anonymized genetic data for up to 850,000 of these variants, including data from 85,000 people who wore wearable sleep trackers for seven days and 250,000 people who completed a sleep preference questionnaire. This provided a more detailed image of up to an hour on how gene mutations affect us when we sleep and wake up.

In the largest of these samples, about one-third of the subjects self-identified as morning lark, 9% stayed up late and the rest were in the middle. Overall, the average midpoint of sleep was 3:00 am. That is, I went to bed at 11 pm and woke up at 6 am.

With this information in hand, researchers turned to another sample containing genetic information, along with anonymized medical and prescription records, and a study of the diagnosis of major depressive disorder.

Using a new statistical method, they asked: Do people with genetic variation that predispose to early rising also have a lower risk of depression?

The answer is certainly yes.

Each midpoint of sleep one hour ago (between bedtime and wake-up time) corresponded to a 23% lower risk of major depressive disorder.

This suggests that if a person who normally goes to bed at 1 am goes to bed late at night and sleeps the same amount of time, the risk can be reduced by 23%. If you go to bed at 11:00 pm, you can save about 40%.

Studies do not show whether people who get up early can benefit from getting up earlier. However, for those in the intermediate or evening range, shifting to an earlier bedtime may help.

What can explain this effect?

Some studies suggest that getting more exposure to light during the day, which early risers are prone to, results in a cascade of hormonal effects that can affect mood.

Others have pointed out that having a body clock, or circadian rhythm, that tends to be different from most people can be disheartening in itself.

“We live in a society designed for the morning people, and the night people often feel that they are always inconsistent with their social clock,” Douglas said.

He emphasizes the need for large, randomized clinical trials to make a clear decision as to whether early bedtime can reduce depression. “But this study does shift the weight of evidence towards supporting the causal relationship of sleep timing to depression.”

For those who want to move to an earlier sleep schedule, Vetter offers this advice:

“Bright during the day and dark at night,” she says. “Put your coffee in the morning on the pouch. If possible, ride your bike to work and dim those electronics in the evening.”