Note per: Several times a year my sleep schedule shifts to "mafia" mode: when civilians fall asleep, I wake up. A couple of years ago I tested the glasses for normalizing sleep , since then I have become interested in sleep, what affects sleep, and what sleep affects. Sleep is important for the brain , but sleep advice can be controversial . I come across a lot of new studies and live hacks about sleep and I decided to share them here on Habré (longreads) and in the telegram: Sleep Hackers (which is not in Habré format).
A new genetic study published in the journal JAMA Psychiatry on May 26 found that waking up an hour earlier reduced the likelihood of depression by 23%.
Researchers at the University of Colorado at Boulder and the Broad Institute of Massachusetts Institute of Technology and Harvard studied 840,000 people and found some of the best evidence that chronotype, or a person's tendency to sleep at a particular hour, influences the risk of depression.
It is also one of the first studies to measure how many or few changes are needed to affect mental health. The results can have serious ramifications as people return to work and study remotely after an epidemic - a trend that has forced many to adjust to later sleep patterns.
"We've known for some time that there is a relationship between sleep time and mood, but we often hear doctors ask how much earlier people go to bed for a benefit?" said study leader Celine Vetter, assistant professor of integrative physiology at CU Boulder. “We found that even moving the time an hour earlier would reduce the risk of depression.”
Previous observational studies have shown that owls, no matter how long they sleep, are twice as likely to suffer from depression as early risers. It was difficult for researchers to figure out what causes this, as mood problems can disrupt sleep habits.
Other studies used a limited number of samples, were based on surveys taken at the same time, or did not take into account environmental elements that can affect both sleep schedule and mood, which skewed the results. In 2018, Wetter published the results of a four-year study of 32,000 nurses, which found that early risers were 27% less likely to suffer from depression.
Team Leader Iyas Douglas, M.D., used data from DNA testing company 23andMe, as well as the UK Biobank biological database, to find out if shifting sleep time is really protecting and how much change is needed. Douglas then applied a technique known as "Mendelian randomization," which relies on genetic correlations to determine cause and effect.
“Our genetics are laid down at birth, so some of the biases that affect other types of epidemiological research usually do not affect genetic research,” said Douglas, who graduated from Harvard Medical School in May.
It is known that more than 340 common genetic variations affect human chronotype, including polymorphisms in the so-called “clock gene” PER2, and heredity accounts for 12–42% of our sleep preferences.
The researchers examined anonymous genetic data for these variations from 850,000 people, including 85,000 people who wore sleep trackers for seven days and 250,000 people who completed a sleep preference questionnaire. This gave them a more detailed picture, down to the hour, of how genetic differences affect when we sleep and wake up.
In the largest of these samples, almost a third of the respondents identified themselves as morning larks, 9% as night owls, and the rest as something in between. The middle of sleep was mostly at 3 a.m., indicating that people went to bed at 11 p.m. and woke up at 6 a.m. With this information, the researchers looked at a separate sample, which contained genetic data, anonymous medical and drug records, and interviews with diagnoses of major depressive disorder. Using modern statistical tools, they found that people with the genetic variation that is responsible for getting up early also had a lower risk of depression.A 23% reduction in major depressive illness was associated with each hour earlier in the midpoint of sleep (halfway between going to bed and waking).
This means you can reduce your risk of depression by 23% by going to bed an hour earlier (for example, not at 1 am, but at midnight). And if you go to bed at 11:00 pm, you can reduce your risk by about 40%. According to research, people who are already waking up early find it helpful to wake up earlier. However, those in the moderate to evening range are likely to benefit from switching to an earlier bedtime.
What could be the cause of this phenomenon?
According to recent research, getting more daylight during the day, like people getting up early in the morning, triggers a chain reaction of hormonal changes that can affect mood. Others argue that having a body clock or circadian rhythm that is different from that of most people can be depressing in itself.
“We live in a society designed for morning people, and evening people often feel like they are constantly out of step with these social hours,” Douglas said.
"This study definitely shifts the weight of the evidence for a causal effect of sleep time on depression," Douglas added.
Dr. Wetter gives the following advice to people looking to sleep earlier: “Keep your days bright and your nights dark,” she says. “Have your morning coffee on the porch. If you can, walk or bike to work and dim all the electronics in the evening. "
Read more
- Sleep is the main resource for the programmer's brain
- How to reprogram sleep patterns: 30 days every morning I shone a bright green light in my eyes
- Sleep gadgets
- Sleep Hackers - telegram channel with live hacks for sleep
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