Study finds that these devices damage people’s sleep and may worsen their health.
Study finds that these devices damage people’s sleep and may worsen their health.
Using e-readers, like an iPad, that emit blue light can disrupt both sleep and general health if read before bedtime, a new study concludes.
Researchers at Brigham and Women’s Hospital compared the effects of reading an iPad in the hours before sleep with reading a traditional paper book.
Dr. Anne-Marie Chang, the study’s first author, explained the results:
“We found the body’s natural circadian rhythms were interrupted by the short-wavelength enriched light, otherwise known as blue light, from these electronic devices.
Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock and reduced next-morning alertness than when reading a printed book.”
In the two-week long study, published in the Proceedings of the National Academy of Sciences, 12 people read an iPad or a printed book for four hours before bedtime over five consecutive nights (Chang et al., 2014).
When people read the iPad they felt less sleepy in the evening, spent less time in rejuvenating REM sleep and their bodies produced less of the sleep-inducing hormone melatonin.
After eight hours sleep, the iPad readers were less alert and felt sleepier.
The results are likely not specific to the iPad, but apply to any devices which emit blue light, like LED monitors, cell phones and laptops.
E-readers such as the original Kindle, which does not emit light, are probably fine.
Professor Charles Czeisler, a distinguished sleep researcher and one of the study’s authors, said:
“In the past 50 years, there has been a decline in average sleep duration and quality.
Since more people are choosing electronic devices for reading, communication and entertainment, particularly children and adolescents who already experience significant sleep loss, epidemiological research evaluating the long-term consequences of these devices on health and safety is urgently needed.”
2. Why some people only need five hours’ sleep a night
While most people can get by with less than six hours sleep, the majority will suffer physically and psychologically, especially if sleep deprived over the long-term.
However, a gene mutation which means a person can function normally with only five hours’ sleep a night has been identified by a new study of 100 pairs of twins.
Those carrying the target gene variant slept, on average, for five hours, which was one hour shorter than their twins without the gene.
When the twins were given cognitive tests after sleep deprivation, those with the gene variant did better, making 40% fewer errors.
Not only that, but the carriers recovered more quickly from sleep deprivation, only requiring 8 hours recovery sleep, compared with their twins who needed 9.5 hours.
Just believing that you’ve slept better than you really have is enough to boost cognitive performance the next day.
The findings comes from a study of 164 people who were given a lecture on how important sleep quality is and told they would be given a new test of how well they had slept the previous night.
After the test, some were told they’d slept well the previous night, others that they’d slept badly.
This had no relationship to how they had actually slept and were just made up to try and convince one group they’d slept better than the other.
Those told they’d slept better scored higher on tests of attention and memory than those told they’d slept poorly.
How you slept last night isn’t just about how you actually slept, it’s also about how you think you slept.
This study suggests that tweaking your mindset a little could be enough to boost your performance.
Failing to get enough sleep causes low mood in teenagers, along with worse health and poor learning.
But it’s not all down to late night video gaming or TV: the part of the brain which regulates the sleep-wake cycle — the Suprachiasmatic Nucleus — changes in puberty.
Teenage brains also secrete less melatonin so their ‘sleep drive’ reduces.
As a result, being forced to rise the next day at 6am for school or college means teens find it hard to get the 8 to 10 hours sleep that they need.
Although hormonal changes are partly to blame for teenage angst, being short of sleep significantly contributes to lack of motivation and poor mood.
We all know that lack of sleep affects our memory, along with other cognitive abilities.
But now new research shows that not getting enough sleep increases the chances your mind will actually create false memories.
In the study, one group of participants were allowed to get a full nights’ sleep, while another had to stay up all night.
In the morning they were given a load of information about a crime — some true, some false — that had been committed.
The results showed that those who’d missed out on their sleep were the most likely to regurgitate the false information, rather than remembering the ‘true’ crime-scene photos they’d been shown moments beforehand.
The lack of sleep had messed with their heads to the extent that all the evidence — right and wrong — had got mixed up.
A new study has found evidence for a long-suspected danger of sleeping pills: an increased risk of death.
The large study looked at data from over 100,000 patients who had been to their family doctors across seven years.
It found that taking sleeping pills, like zolpidem/Ambien, doubled the risk of death.
Professor Scott Weich, who led the study, said:
“That’s not to say that they cannot be effective.
But particularly due to their addictive potential we need to make sure that we help patients to spend as little time on them as possible and that we consider other options, such as cognitive behavioural therapy, to help them to overcome anxiety or sleep problems.”
9. Sleep drunkenness disorder affects one in seven
As many as one in seven people may be affected by ‘sleep drunkenness disorder’ soon after they’ve woken up or during the morning.
Sleep drunkenness disorder involves severe confusion upon wakening — way more than just the usual morning grogginess — and/or inappropriate behaviour: things like answering the phone instead of turning off the alarm.
Confused awakenings can happen to people when very short of sleep or jet-lagged, but are regular occurrences for those with the disorder.
Researchers have found that 15% of people had experienced at least one episode of sleep drunkenness in the last year.
People who realise they are in a dream while they are dreaming — a lucid dream — have better problem-solving abilities, new research finds.
This may be because the ability to step outside a dream after noticing it doesn’t make sense reflects a higher level of insight.
Around 82% of people are thought to have experienced a lucid dream in their life, while the number experiencing a lucid dream at least once a month may be as high as 37%.
Dr Patrick Bourke, who led the study, said:
“It is believed that for dreamers to become lucid while asleep, they must see past the overwhelming reality of their dream state, and recognise that they are dreaming.
The same cognitive ability was found to be demonstrated while awake by a person’s ability to think in a different way when it comes to solving problems.”
New sleep centre discovered and neuroscientists succeed in turning it on and off using a virus.
New sleep centre discovered and neuroscientists succeed in turning it on and off using a virus.
A circuit in the brain that promotes deep sleep, which reinvigorates the brain from its daily activities, has been identified for the first time by neuroscientists using an innovative new method.
The ‘sleep-node’ — the second to be discovered — lies deep in the ancient part of the brain and is vital in sending us off into a ‘slow-wave’ or deep sleep, which is one of the stages of sleep we cycle through during the night.
The area is in the parafacial zone (PZ) in the brain stem, and it produces half of all the brain’s sleep-promoting activity.
The brain stem controls our most basic functions like breathing, heart rate, blood pressure, temperature — and sleep.
Neuroscientists used a sophisticated new approach to turn this region of the brain on and off in mice (Anaclet et al., 2014).
Patrick Fuller, one of the study’s authors, explains:
“To get the precision required for these experiments, we introduced a virus into the PZ [parafacial zone] that expressed a ‘designer’ receptor on GABA neurons only but didn’t otherwise alter brain function.
When we turned on the GABA neurons in the PZ, the animals quickly fell into a deep sleep without the use of sedatives or sleep aids.”
How the parafacial zone in the brain stem interacts with other areas of the brain is not yet known, but this is an important new tool in investigating the function of different areas of the brain.
Christelle Ancelet, another of the study’s authors, said:
“These new molecular approaches allow unprecedented control over brain function at the cellular level.
Before these tools were developed, we often used ‘electrical stimulation’ to activate a region, but the problem is that doing so stimulates everything the electrode touches and even surrounding areas it didn’t.
It was a sledgehammer approach, when what we needed was a scalpel.”
Caroline E. Bass, another of the study’s authors, commented:
“We are at a truly transformative point in neuroscience, where the use of designer genes gives us unprecedented ability to control the brain.
We can now answer fundamental questions of brain function, which have traditionally been beyond our reach, including the ‘why’ of sleep, one of the more enduring mysteries in the neurosciences.”
The scientists hope the findings will eventually lead to new treatments for sleep disorders like insomnia.
This research could lead to a cure for jet-lag and other sleep problems.
This research could lead to a cure for jet-lag and other sleep problems.
Researchers at the Salk Institute for Biological Studies have found that a single gene regulates daily sleeping and waking cycles (Hatori et al., 2014).
Understanding the function of the gene, called Lhx1, may help to create therapies for jet-lagged travellers, night-shift workers and those with problems sleeping.
Satchidananda Panda, who led the research, says that even dementias may be helped by potential therapies:
“It’s possible that the severity of many dementias comes from sleep disturbances.
If we can restore normal sleep, we can address half of the problem.”
The study examined the sleep and wake cycles of mice, concentrating on an area of the brain called the suprachiasmatic nucleus, or the SCN.
The SCN is a densely packed region of around 20,000 neurons in the hypothalamus, which establish our daily biological rhythms.
Sometimes known as the ‘master clock’, the SCN effectively tells every cell in the body what time it is.
Our internal clock is reset by light, which is why we tend to suffer from jet lag: our daily biological cycles get scrambled.
The researchers in this study effectively gave jet lag to the mice by shifting their usual day-night cycle by 8 hours.
They then looked at the expression of 213 genes and were surprised to find that just one was suppressed in response to light, T
The finding was a particular surprise because previously the gene had never been intricately linked with SCN function.
They found that mice that had little or no Lhx1 were able to adjust to the jet-lag much faster than other mice.
The scientists hope that this brings them one step closer to new cell regenerative therapies for sleep problems.
The physical changes in the motor cortex that result from learning and sleep.
The physical changes in the motor cortex that result from learning and sleep.
Sleep after learning encourages brain cells to make connections with other brain cells, research shows for the first time.
The connections, called dendritic spines, enable the flow of information across the synapses.
The findings, published in the prestigious journal Science, are the first to show physical changes in the motor cortex resulting from learning and sleep (Yang et al., 2014).
One of the study’s authors, Wen-Biao Gan, PhD, said:
“We’ve known for a long time that sleep plays an important role in learning and memory. If you don’t sleep well you won’t learn well.
But what’s the underlying physical mechanism responsible for this phenomenon?
Here we’ve shown how sleep helps neurons form very specific connections on dendritic branches that may facilitate long-term memory.
We also show how different types of learning form synapses on different branches of the same neurons, suggesting that learning causes very specific structural changes in the brain.”
The results come from studies in mice, which were genetically engineered with a fluorescent protein in their neurons.
With the use of a laser-scanning microscope, the fluorescent protein allowed the scientists to track and image the dendritic spines before and after they learnt a new skill; in this case balancing on a spinning rod.
Some of the mice were allowed to sleep after they had learned to balance on the rod, others were not.
In the brains of those that had slept, there was more growth of dendritic spines.
In addition, the type of task the mice learnt –whether they ran forward or backward across the rod — affected where the dendritic spines grew.
Gan continued:
“Now we know that when we learn something new, a neuron will grow new connections on a specific branch.
Imagine a tree that grows leaves (spines) on one branch but not another branch. When we learn something new, it’s like we’re sprouting leaves on a specific branch.”
“…students described the amount of homework each night as “overwhelming,” “unmanageable,” or “more than [they] could handle,””
“…students described the amount of homework each night as “overwhelming,” “unmanageable,” or “more than [they] could handle,””
According to new research, too much homework is associated with academic stress, a lack of balance in children’s lives and even physical health problems.
The new study into 4,317 students at 10 high-performing US high schools questions whether the average of 3 hours homework per night is really justified (Galloway et al., 2013).
The researchers asked students about the work they were doing and discovered that:
“Some of the students described the amount of homework each night as “overwhelming,” “unmanageable,” or “more than [they] could handle,” with one describing the load as “an endless barrage of work.””
One student wrote:
“There’s never a time to rest. There’s always something more you should be doing. If I go to bed before 1:30 I feel like I’m slacking off, or just screwing myself over for an even later night later in the week… There’s never a break. Never.”
The knock-on effects of all this homework were felt in both their sleep quality and their health:
“Many complained that the workload led to sleep deprivation and other health problems. Students described homework as the “main reason” preventing them from getting the recommended 9.25 hr of sleep each night.”
This feedback was supported by measures of the amount of homework students did and their well-being and engagement:
“Students who spent more hours on homework tended to be more behaviorally engaged in school, but were simultaneously more stressed about their school work and tended to reportmore physical symptoms due to stress, fewer hours of sleep on school nights, less ability to get enough sleep, and less ability to make time for friends and family.”
But surely all this homework is necessary and important?
Apparently not:
“…students will often do work they see as “pointless,” “useless,” and “mindless” because their grades will be affected if they do not. This kind of busy work, by its very nature, discourages learning and instead promotes doing homework simply to get points.”
All of this doesn’t mean homework should be banned, but 3 hours a night on average? Seriously?
The authors conclude by saying:
“Given the negative outcomes we find associated with more time spent on homework, our study calls into question the desirability of such diligence and the utility of assigning large quantities of homework in high-performing schools.
[…] any homework assigned should have a purpose and benefit, and it should be designed to cultivate learning and development.”
It seems the horrible, wasteful, idiotic culture of pointless ‘busywork’ is alive in well in some high schools.
Exposure to blue light can improve reaction times, attention and boost brain waves, according to a new study.
Exposure to blue light can improve reaction times, attention and boost brain waves, according to a new study.
With so many people working indoors–and with natural light lacking in the winter months–a new study could have important implications for the design of artificial lighting (Rahman et al., 2014).
The research, conducted at Brigham and Women’s Hospital in Boston, exposed some participants to short-wavelength or blue light and others to green light. They carried on with their normal day-to-day activities under the light for 6.5 hours.
Afterwards those who’d been exposed to blue light had faster auditory reaction times, better attention and their brain wave patterns suggested they were more alert–although they didn’t consciously feel any more alert.
Shadab Rahman, the lead author, explained:
“Our previous research has shown that blue light is able to improve alertness during the night, but our new data demonstrates that these effects also extend to daytime light exposure. These findings demonstrate that prolonged blue light exposure during the day has an alerting effect.”
These findings come on top of findings from the same researchers that exposing people to blue light at night also increases alertness.
When people are illuminated with a blue light at night it brings their alertness up close to daytime levels.
Neuroscientist Steven Lockley, one of the study’s authors, said:
“These results contribute to our understanding of how light impacts the brain and open up a new range of possibilities for using light to improve human alertness, productivity and safety. While helping to improve alertness in night workers has obvious safety benefits, day shift workers may also benefit from better quality lighting that would not only help them see better but also make them more alert.”
It is hoped that smart lighting system which deliver the right wavelengths of light will be more widely available in the future.
First study to demonstrate emotional awareness in patients in a persistent vegetative state.
First study to demonstrate emotional awareness in patients in a persistent vegetative state.
It has long been thought that patients who are in a vegetative state–frequently due to a traumatic brain injury–have no awareness of their environment or themselves.
A new study using fMRI brain imaging, though, shows that some patients can display emotional reactions to pictures of loved ones (Sharon et al., 2013).
The study is surprising because patients in this condition show no signs of being aware of their surroundings. They breathe on their own, sleep and wake up, but otherwise appear utterly unresponsive to what’s going on around them.
Their families naturally wonder if they even realise they are there.
Responding to loved ones
The new study, though, put four patients who were in a persistent vegetative state (PVS) in a brain scanner and showed them pictures, some of people they knew and some of strangers.
These results were compared with those from a healthy control group.
For two PVS patients, the brain scans suggested emotional awareness.
One patient in particular–a 60-year-old woman who had been hit by a car–showed brain activity in the emotional and face-processing areas of the brain when looking at pictures of loved ones.
Similar activity was also seen when she was asked to imagine her parents’ faces.
The study’s first author, Dr. Haggai Sharon explained:
“This experiment, a first of its kind, demonstrates that some vegetative patients may not only possess emotional awareness of the environment but also experience emotional awareness driven by internal processes, such as images.”
The two patients who showed emotional awareness actually regained consciousness within two months of being tested. Neither remembered anything from when they were unconscious.
It’s possible the test may provide a clue about the patient’s prognosis and even point the way towards useful therapies for those in a persistent vegetative state.
A recent study has revealed exactly how a lack of sleep may lead to junk food cravings.
Recent studies reveal exactly how a lack of sleep may lead to junk food cravings.
Recent research from UC Berkeley scanned the brains of 24 participants after both a good, and a bad, night’s sleep (Greer et al., 2013).
After disturbed sleep, there was increased activity in the depths of the brain, which is generally associated with rewards and automatic behaviour.
The frontal lobes, just behind and above the eyes, which help provide self-control, were less active.
The finding may help explain why the sleep-deprived are more likely to give in to calorific temptations.
One of the study’s authors, Matthew Walker, explained:
“What we have discovered is that high-level brain regions required for complex judgments and decisions become blunted by a lack of sleep, while more primal brain structures that control motivation and desire are amplified.”
In other words: lack of sleep robs people of their self-control and so their good intentions are quickly forgotten.
On top of this, the researchers found that after being deprived of sleep, participants displayed greater craving for high-calorie junk food. The more sleep-deprived they were, the greater the cravings.
By contrast, when they were well rested, the same people were better able to resist temptation.
Bring me burgers!
This study is the latest in a wave of recent research examining the link between lack of sleep and poor dietary choices.
A study of 13,284 teenagers found that those who slept poorly also made poor decisions about food.
Similarly, a Swedish study found that at a buffet, tired people were more likely to load up their plates (Hogenkamp et al., 2013).
The link has even been made from poor sleep through to food shopping.
A Swedish study found that men who were sleep-deprived bought, on average, 9% more calories than those who’d had a good night’s sleep (Chapman et al., 2013). These results were likely the result of the poor decision-making identified by the UC Berkeley study.
It had been thought that the tendency to eat more after poor sleep was related to the so-called ‘hunger hormone’ ghrelin. But the latest studies suggest that it’s simple self-control that is most important in causing the sleep-deprived to over-indulge.
Dr Lauren Hale, author of the study of teenagers, said:
“If we determine that there is a causal link between chronic sleep and poor dietary choices, then we need to start thinking about how to more actively incorporate sleep hygiene education into obesity prevention and health promotion interventions.”
A nap as short as 6 minutes after learning can help to consolidate learning and improve performance.
A nap as short as 6 minutes after learning can help to consolidate learning and improve performance.
It’s been more than a century since the first scientific evidence was produced that sleep benefits memory.
But the man who stumbled on it, German psychologist Hermann Ebbinghaus, couldn’t believe that learning during sleep could explain anomalies in his results, and he rejected the possibility.
It wasn’t until forty years later that the power of ‘the sleep effect’ was demonstrated directly (Jenkins & Dallenbach, 1924).
Since then, studies have been carried out to find out what types of memory are affected by sleep, how much sleep is required and how the effect occurs.
For example, people have asked: is it just memory for facts, or does it also work for physical movements?
The interest in the effect is hardly surprising: the idea that you can learn while unconscious is one more beautiful thing about sleep.
Learn while you sleep
Here’s a recent example of a typical study investigating the effect.
Payne et al (2012) had people learn a series of word-pairs, like RIDER and SWITCH, either at 9am in the morning or 9pm at night.
There were then tested at 30 minutes after learning, 12 hours later and 24 hours later.
The results showed that whether they learned in the morning or evening, it made little difference to their recall just 30 minutes later.
But, over a longer delay, differences did emerge.
The people who had learned the word-pairs before bed performed better than those that had learned them in the morning.
These are not isolated results. Fenn and Hambrick (2012) carried out a similar study and got the same result: people who learned before they slept did better than those who followed the learning with a period of wakefulness.
These researchers also found that some people, those with a better ‘working memory’, were particularly good at learning while they slept.
Six-minute benefit
There is now all sorts of research showing that different types of learning are improved by a subsequent period of sleep.
For example, procedural learning–like that involved in playing tennis or learning fingering on the piano–is improved by subsequent periods of sleep.
Similarly, perceptual learning–like being able to distinguish two notes from each other–has also shown improvements from subsequent periods of sleep.
Researchers then wondered how short the sleep can be to see the benefits.
It turns out that you’re better off to learn new information before your full eight hours. But benefits to learning have been shown in one study for a nap as short as six minutes (Lahl, 2008).
Learning offline
Scientists aren’t exactly sure why learning benefits from sleep. The old theory used to be that everyday events interfered with newly learned memories causing them to fade away or get muddled. In other words, sleep was better after learning because no new memories could interfere.
Now, though, many psychologists believe that there is an active process at work while we sleep.
During the unconscious period, our minds may be working on the memories and more strongly encoding them for later retrieval.
This may be part of the reason why, like many others, John Steinbeck pointed out:
“It is a common experience that a problem difficult at night is resolved in the morning after the committee of sleep has worked on it.”
