Sleep duration provides important clues about both mental and physical health.
Millions suffer from insomnia, but few get the treatment that actually works—here’s why.
The study of 32,000 nurses is the largest ever to look at the link between depression and chronotype.
The study of 32,000 nurses is the largest ever to look at the link between depression and chronotype.
Women who go to bed early and rise early are less likely to develop depression.
Studies have also found that both men and women who are ‘early birds’ have a lower depression risk.
This study of 32,000 nurses is the largest ever to look at the link between depression and chronotype.
Chronotype is the technical term for whether you are naturally early to bed and early to rise, or late to bed and late to rise — or, somewhere in between.
Among the nurses, 53 percent described themselves as intermediate, 10% as evening types and 37 percent as early risers.
The women were followed for four years to see who developed depression.
Dr Céline Vetter, the study’s first author, explained the results:
“Our results show a modest link between chronotype and depression risk.
This could be related to the overlap in genetic pathways associated with chronotype and mood.”
The increased risk for evening types was between 12 percent to 27 percent.
This was after other risk factors had been taken into account, such as being a smoker and having an erratic sleep pattern.
Dr Vetter said:
“This tells us that there might be an effect of chronotype on depression risk that is not driven by environmental and lifestyle factors.”
Genetics plays a fairly large role in whether you are an early bird or a night owl.
However, there are other factors, Dr Vetter said:
“Alternatively, when and how much light you get also influences chronotype, and light exposure also influences depression risk.
Disentangling the contribution of light patterns and genetics on the link between chronotype and depression risk is an important next step.”
The study does not tell us that all night owls are doomed to be depressed and there are also ways of lowering the risk.
Dr Vetter advises:
“Being an early type seems to beneficial, and you can influence how early you are.
Try to get enough sleep, exercise, spend time outdoors, dim the lights at night, and try to get as much light by day as possible.”
The study was published in the Journal of Psychiatric Research (Vetter et al., 2018).
The most popular genre of music for better sleep.
The most popular genre of music for better sleep.
Two-thirds of people use music to help them sleep.
People believe that music helps them sleep by blocking out noises and distracting them from wakeful thoughts.
Indeed, studies are starting to show that music can be an effective sleep aid.
The three most popular reasons people endorse for how music helps them sleep are:
People felt that music helps them clear their mind of racing thoughts and gives it something to focus on.
It also puts people in a good mood before they drop off.
For some people, music eases them into a dream-like state, which soon turns to sleep.
For others, music is comforting and soothing.
Some people simply liked to know how long they took to fall asleep and music helped them gauge it.
Classical music was the most popular genre people used to help them sleep, followed by rock, pop and acoustic.
Here is the full list, from most to least frequently used:
The conclusions come from a survey of 651 people of all ages.
The results showed that more than one-third said they used music at least weekly to help them fall asleep.
Many regularly used music for sleep despite not having a disorder of any kind.
The study’s authors write:
“The largest ever survey of everyday use of music for sleep reveals multiple pathways to effect that go far beyond relaxation; these include auditory masking, habit, passion for music, and mental distraction.
This work offers new understanding into the complex motivations that drive people to reach for music as a sleep aid and the reasons why so many find it effective.”
The study was published in the journal PLoS ONE (Trahan et al., 2018).
Science is uncovering fascinating ways sleep—or the lack of it—shapes who we are and how we feel.
How sleep helps us adapt our memories for future experiences.
How sleep helps us adapt our memories for future experiences.
Sleep helps to strengthen both old and new versions of an experience.Instead of overwriting old versions of a memory, the brain stores another copy of the same experience.Sleep keeps both old and new memories alive, which gives memory more flexibility.Dr Scott Cairney, who led the research said:“Previous studies have shown sleep’s importance for memory.Our research takes this a step further by demonstrating that sleep strengthens both old and new versions of an experience, helping us to use our memories adaptively.In this way, sleep is allowing us to use our memory in the most efficient way possible, enabling us to update our knowledge of the world and to adapt our memories for future experiences.”For the study people were learning the locations of words on a screen over two learning sessions.One group slept between learning sessions for 90 minutes, the other did not.The catch was that some of the words moved between training session.Those that slept in between had better memory for both the original location and the updated location.This suggested sleep had had a positive effect on both the new and old version of the memory.Professor Gareth Gaskell, study co-author, said:
“For the sleep group, we found that sleep strengthened both their memory of the original location as well as the new location.In this way, we were able to demonstrate that sleep benefits all the multiple representations of the same experience in our brain.”Curiously, the study may also show how some inaccuracies in memories arise.After all, if we are carrying around multiple memories of the same thing, then it is easy for us to get confused.The study was published in the journal Cortex (Cairney et al., 2017).
How memories and dreams come together to help us solve problems at night.
How memories and dreams come together to help us solve problems at night.
Ever wondered why sleeping on a problem can make the answer seem clear?
Now, sleep scientists think they have a plausible theory.
While we sleep our brains shuttle backwards and forwards between different types of sleep.
Two of these together may provide the key to how we can solve problems overnight.
So-called ‘non-REM’ sleep helps us organise information.
REM stands for Rapid Eye Movement and this is the part of sleep in which we dream.
‘Non-REM’, then, is the part when we are not dreaming — sometimes when we are in deep sleep.
Then, REM sleep allows us to make unexpected connections between different memories.
This could be the source of our nighttime Eureka moments.
Professor Penny Lewis, the study’s first author, explained:
“Suppose I give you a creativity puzzle where you have all the information you need to solve it, but you can’t, because you’re stuck.
You could think of that as you’ve got all the memories that you need already, but you need to restructure them — make links between memories that you weren’t linking, integrate things that you weren’t integrating.”
During non-REM sleep, the hippocampus — a part of the brain critical to memory — decides what memories to replay.
Then, during REM sleep, when we dream, the brain is free to replay stored memories in any combination.
Hence the jumble of juxtapositions we get while dreaming.
Next morning the answer pops into our heads, seemingly unbidden, but actually the result of serious memory crunching.
Professor Lewis said:
“So, what we propose is that, if you’re stuck on some kind of problem, that problem is salient, and we know that salient things are replayed.
The slightly hypothetical part is that, when something else is randomly activated in the cortex that has an element that’s similar, you’ll form a link.”
The study was published in the journal Trends in Cognitive Sciences (Lewis et al., 2018).
How sleepiness transforms your habitual behaviours.
What you eat today could impact how well you sleep tonight.
Up to 10 percent of road traffic accidents have this psychological cause.
Up to 10 percent of road traffic accidents have this psychological cause.
Drowsiness is a major cause of road traffic accidents, involved in up to 10 percent of crashes.
The natural vibrations of a car make people sleepy just 15 minutes after setting off.
People reach significant levels of drowsiness after 30 minutes and peak drowsiness after 60 minutes.
The Australian researchers hope the finding can be used to help design new seats to keep drivers awake.
Professor Stephen Robinson, who led the study, said:
“We know 1 in 5 Australians have fallen asleep at the wheel and we know that drowsy driving is a significant issue for road safety.
When you’re tired, it doesn’t take much to start nodding off and we’ve found that the gentle vibrations made by car seats as you drive can lull your brain and body.
Our study shows steady vibrations at low frequencies — the kind we experience when driving cars and trucks — progressively induce sleepiness even among people who are well rested and healthy.
From 15 minutes of getting in the car, drowsiness has already begun to take hold. In half an hour, it’s making a significant impact on your ability to stay concentrated and alert.
To improve road safety, we hope that future car seat designs can build in features that disrupt this lulling effect and fight vibration-induced sleepiness.”
Dr Mohammad Fard, study co-author, said:
“We want to study a larger cohort, particularly to investigate how age may affect someone’s vulnerability to vibration-induced drowsiness as well as the impact of health problems such as sleep apnea.
Our research also suggests that vibrations at some frequencies may have the opposite effect and help keep people awake.
So we also want to examine a wider range of frequencies, to inform car designs that could potentially harness those ‘good vibrations’.”
The study was published in the journal Ergonomics (Zhang et al., 2018).
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