Waking up just one hour earlier could reduce the risk of depression by 23 per cent, a new genetic study reveals.
Researchers at University of Colorado Boulder analysed the genetic data of nearly 840,000 adults of European ancestry.
They found a link between earlier sleep timing patterns – getting up and going to bed early – and lower risk of a ‘major depressive disorder’.
It’s possible that the greater exposure to light during the day results in ‘a cascade of hormonal impacts’ that can influence mood.
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The study suggests those suffering from depression would benefit by getting up just an hour earlier (stock image)
RECOMMENDED SLEEP DURATION
– Preschool (3-5 years): 10-13 hours
– School-age (6-13 years): 9-11 hours
– Teen (14-17 years): 8-10 hours
– Young adult (18-25) 7-9 hours
– Adult (26-64): 7-9 hours
– Older adult (65 or more) 7-8 hours
Source: Sleep Foundation
‘We have known for some time that there is a relationship between sleep timing and mood,’ said study author Celine Vetter, an assistant professor of integrative physiology at CU Boulder.
‘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.’
For those wanting to shift themselves to an earlier sleep schedule, Vetter says: ‘Keep your days bright and your nights dark.
‘Have your morning coffee on the porch. Walk or ride your bike to work if you can, and dim those electronics in the evening.’
For their study, the team focused on genetics, which collectively explains somewhere between 12 to 42 per cent of our sleep timing preferences, they say.
Using data from the DNA testing company 23 and Me and the biomedical database UK Biobank, the researchers assessed deidentified genetic data on these variants from the 840,000 adults.
This total included data from 85,000 people who had worn wearable sleep trackers for seven days and 250,000 who had filled out sleep-preference questionnaires.
In the largest of these samples, a third of surveyed subjects self-identified as morning larks (someone who goes to bed early and gets up early) and nine per cent as night owls (goes to bed and gets up late). The rest were somewhere in the middle.
Overall, the average sleep mid-point was 3am, meaning they went to bed at 11pm and got up at 6am.
Researchers then looked at genetic information along with anonymised medical and prescription records and surveys about diagnoses of major depressive disorder.
It’s possible that the greater exposure to light during the day results in ‘a cascade of hormonal impacts’ that can influence mood (stock image)
Getting less than five hours of sleep a night can DOUBLE your risk of developing dementia, study warns
Getting five hours or less of sleep a night doubles the risk of getting dementia, a new study warns.
Researchers from Brigham and Women’s Hospital in Boston looked at data from 2,812 US adults aged 65 and over.
‘Very short’ sleep duration, defined as five hours or less, doubled the risk of dementia compared to the ‘recommended’ duration of seven to eight hours, they found.
The study backs up previous research that too little sleep essentially ‘sets the stage’ for forms of dementia like Alzheimer’s.
While this study didn’t look at the reason behind the link, it’s possible that a lack of proper rest prevents the brain from clearing out the toxins that trigger an ongoing decline in brain function.
The individuals with genetic variants predisposing them to be early risers also had a lower risk of depression, the team found.
Each one-hour earlier sleep midpoint (halfway between bedtime and wake time) corresponded with a 23 per cent lower risk of major depressive disorder.
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 were to go to bed at 11pm, they could cut depression risk even more – by about 40 per cent.
It’s unclear from the study whether those who are already early risers could benefit from getting up even earlier.
But for those in the intermediate range or ‘nightowl’ range, shifting to an earlier bedtime would likely be helpful.
The team used the ‘mendelian randomization’ for their study – an epidemiological technique that uses differences in genetic to distinguish a simple correlation from causation (one factor directly causing another).
‘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 lead study author Iyas Daghlas at Harvard University.
‘This study definitely shifts the weight of evidence toward supporting a causal effect of sleep timing on depression.’
Previous research has advanced understanding of the circadian rhythm or ‘clock’, which regulates when exactly we become sleepy and when we’re more alert.
One of the proteins critical for determining the timing of the clock, as well as the timing of sleep, is Period2, or PER2.
PER2 is a protein in mammals encoded by the PER2 gene.
More than 340 common genetic variants, including variants in the so-called ‘clock gene’ PER2, are known to influence a person’s chronotype – a propensity to sleep at a certain time.
The research team believe theirs is some of the strongest evidence yet that chronotype influences depression risk.
A large randomised clinical trial is necessary to determine definitively whether going to bed early can reduce depression, Daghlas added.
The study has been published in the journal JAMA Psychiatry.
What is depression?
While it is normal to feel down from time to time, people with depression may feel persistently unhappy for weeks or months on end.
Depression can affect anyone at any age and is fairly common – approximately one in ten people are likely to experience it at some point in their life.
Depression is a genuine health condition which people cannot just ignore or ‘snap out of it’.
Symptoms and effects vary, but can include constantly feeling upset or hopeless, or losing interest in things you used to enjoy.
It can also cause physical symptoms such as problems sleeping, tiredness, having a low appetite or sex drive, and even feeling physical pain.
In extreme cases it can lead to suicidal thoughts.
Traumatic events can trigger it, and people with a family history may be more at risk.
It is important to see a doctor if you think you or someone you know has depression, as it can be managed with lifestyle changes, therapy or medication.
Source: NHS Choices