Just thinking you had a better night sleep creates a placebo effect that can improve your cognitive abilities, a new study has found. 
 
 Researchers at Colorado College found students who were told they had a good night’s sleep, even if they did not, performed better on attention and memory skill tests than those who had been informed they had slept badly. 
 
 Research led by Christina Draganich and Colorado College Psychology Professor Kristi Erdal involved 164 students who were told a new technique, which does not actually exist, would be used to measure their sleep pattern from the night before. 
 
 Researchers randomly split participants into “above average” quality sleep and “below average” quality sleep groups. Students in both groups were also given a five minute talk on sleep quality and how important it is for cognitive function. They were told the average proportion of REM sleep a night was between 20 and 20 per cent. 
 
 Participants were then connected to a machine they were told would measure their brainwave frequency and shown spreadsheets and formulas. 
 
 Those in the "above average" sleep quality condition were told by researchers they had spent 28.7 per cent of their total sleep time in REM, whereas those in the "below average" sleep quality condition were informed that they had only spent 16.2 per cent of their time in REM sleep. 
 
 The students who were told they got a good night’s sleep performed significantly better in the Paced Auditory Serial Addition Test, a cognitive exercise which measured their ability to listen and process information. 
 
 The authors say what the students were told about their sleep is known as “placebo sleep.” The effect of that information was a placebo effect, which has to do with the person’s mindset regarding his or her treatment. 
 
 They concluded: “These findings supported the hypothesis that mindset can influence cognitive states in both positive and negative directions, suggesting a means of controlling one's health and cognition.” 
 
 The study Placebo Sleep Affects Cognitive Functioning is published in the Journal of Experimental Psychology: Learning, Memory and Cognition. ||||| The bed must be reserved as a place for sleep and sex only. That was the decree of psychologist Richard Bootzin in his influential 1972 proposal for a "stimulus-control" approach to better sleep. One central tenet was operant conditioning: The bed must be a sanctuary, such that the brain is trained to sleep when it is in the bed. The allowance for sex—which, in its ideal form, is one of the most stimulating things a human body can experience—always seemed to me at odds with the stimulus-control approach. A note to aspiring self-help writers: The book For Better Sleep, Kitchen Sex remains unwritten. Otherwise, though, the idea of stimulus control made sense to a lot of people. It also included advice to avoid bedroom behaviors that abet anxiety, like clock-watching. And Bootzin's approach to insomnia endured, proving itself in several studies. So last year when Charles Czeisler, a professor of sleep medicine at Harvard Medical School, found that around 90 percent of Americans use some kind of electronic device within the hour before bed—and correlated the degree of use with ever-poorer sleep—one of his first theories of the case was overstimulation. That's because, Czeisler and colleagues wrote in the Journal of Clinical Sleep Medicine in December of 2013, "In addition to making phone calls, cell phones now allow the user to instant message, listen to music, send emails, play games, and surf the Internet." So they do. And all of that stimulation, the researchers proposed, may "impede the natural withdrawal of sympathetic nervous system activity necessary for sleep onset." Or, preclude one's ability to chill. To what degree is the light from a device, not the cognitive stimulation it provides, responsible for the known sleep effects of screens? A more vague hypothesis raised by Czeisler at the time was that the detrimental effects on sleep might be due to "light and electromagnetic transmissions from technological devices." Other researchers, too, have lately blamed the light exposure element, which is well understood to influence sleep patterns through photoreceptors in the retina that tell the brain to release the hormone melatonin. It flows forth from the pineal gland into the blood and around the body. Normally, melatonin levels rise before bedtime, peak in the middle of the night, and decrease in the early morning. That is why daily light-dark cycles are important for normal levels of alertness and sleep in most people. Abnormalities in these cycles are the basis for shift-work sleep disorder. But to what degree is the light from a device, not the cognitive stimulation it provides, responsible for the known sleep effects of screens? And is that light worse than, say, the light from a light bulb? In research published today in the journal Proceedings of the National Academy of Sciences, Czeisler and colleagues made an interesting advance in understanding that idea, and just how screens themselves tell our brains to stay awake. It began with the mundane observation that people read to unwind—often at night, often in bed. As far as sleep is concerned, Czeisler wondered, does it matter whether those people read books on iPads, Kindles, or paper? 
 
 Czeisler and colleagues, including lead researcher Anne-Marie Chang, an associate neuroscientist in the division of sleep medicine at Harvard Medical School, recruited a small group of people for an intensive experiment. For two weeks, participants took up residence in a monitoring unit at the clinical investigation center at Boston's Brigham and Women's Hospital. The subject group was only 12 people, but for a trial that requires so much commitment, that is not an unimpressive number. Though it was an enviable situation, in some ways: The people were allotted an idyllic eight hours for sleep, from 10:00 p.m. to 6:00 a.m.—a schedule they kept for three weeks prior, as well, in preparation. They were also allotted four hours of undisturbed reading time each night. The elements of a changing world, from technology and business to politics and culture. 
 
 Read More For five days in a row, the people read either a book or an iPad for four hours prior to sleep. Both were kept at constant, preordained distances from the person's face. Chang and colleagues monitored the people's sleep patterns with electroencephalograms all night. Each person did one stint with the iPad, and one with the book. Before and after each trial period, the people underwent hourly blood tests to paint a day-long picture of just how much melatonin was in their veins at any given time. When subjects read on the iPad as compared to the paper books (hereafter referred to as "books"), the people reported feeling less sleepy at night and less alert the following morning. Of course, this is not a blinded study, the kind with a placebo—the participants could have been biased in reporting how they felt. But, empirically, they also took longer to fall asleep on the iPad nights and spent less time in the REM phase of sleep. And the blood tests showed that on average, the brain's melatonin secretion on those nights was delayed by an hour and a half. Though this experiment dealt exclusively with iPads, the researchers also tested the light-emission patterns of other tablets, as well as phones and laptops. Chang told me they all emitted similar patterns, enriched for short-wavelength blue light, and at a similar intensity. So she would expect similar clinical findings for any such device. ||||| One way to have more time for work and play every day is to sleep a little bit less. But eventually, staying awake for longer periods can have a negative impact on the quality of our lives. So where does the break-even point lie, and can it be shifted? 
 
 What You Stand To Lose 
 
 Few things do your body better than a good night's rest. While many of its molecular and cellular mechanisms remain unresolved, we know that sleep helps us consolidate memories , fight infection and manage stress – all while contributing to the maintenance and repair of just about every tissue in our bodies. Meanwhile, a lack of sleep can affect everything from your performance at work to your performance in bed. Foregoing sleep for extended periods of time has been shown to cause your body's metabolism to go haywire. High blood pressure. Obesity. Heart disease. Diabetes. They're all tied to a lack of sleep and crummy sleep habits – what researchers refer to as poor sleep hygiene. "Sleep services all aspects of our body in one way or another: molecular, energy balance, as well as intellectual function, alertness and mood," says sleep expert Dr. Merrill Mitler, a neuroscientist at the National Institutes of Health. 
 
 One of the most extensive human sleep deprivation studies ever conducted sheds light on what happens when our bodies are deprived of the sleep they need. Researchers led by Hans Van Dongen, professor of sleep and chronobiology in the Department of Psychiatry at the University of Pennsylvania, limited study volunteers to various levels of sleep deprivation for 14 consecutive days (for example, 6 hours in bed per night for two weeks straight). The researchers then compared test participants' cognitive and physiological abilities at the end of this period to those of test participants who had gone one, two, and three nights without sleep. 
 
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 Their results showed that restricting sleep to six hours per night caused cognitive performance and reaction times to drop so dramatically, that by the end of the 2-week period, these test participants were performing as poorly as subjects who had forgone sleep entirely for two nights straight. 
 
 What little evidence there is for people acclimating to less sleep comes from a 2009 study conducted by scientists at Walter Reed Army Institute of Research. Researchers led by Thomas Balkin, chairman of the National Sleep Foundation, investigated the effects of "sleep banking" by having test subjects spending ten hours in bed every night for a week. When members of this "extended" sleep group were subsequently deprived of sleep, their performance on motor and attentional tasks suffered less than that of participants in the "habitual" sleep group, who had not been allowed to "bank" sleep in advance, but had rather stuck to their normal sleep schedule. 
 
 Photo Credit: Davide Cassanello via flickr | CC BY 2.0 
 
 It would be inaccurate, however, to say that members of the extended sleep group had conditioned themselves to require less sleep. They still performed worse on the motor and attentional tasks than they would have if they were fully rested. What' more, their dleep-deprived performance was only compared to that of the habitual sleep group for five days. It stands to reason that this performance gap would shrink to zero over time. Consider, also, that the average time in bed for test subjects who were not allowed to "bank" sleep was 7 hours. That's time in bed, not time spent sleeping. Given that sleep experts recommend most adults get between 7 and 8 hours of sleep a night, it's likely that members of the habitual group started the experiment with a handicap, and that that the test subjects who were forced to spend a few extra hours in bed were getting closer to the amount of sleep they actually needed. 
 
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 To summarize: Your body must have sleep. Full stop. As of 2014, there is no strong evidence that a person can condition his or her body over time to require less sleep. "The fact is," says Mitler, "when we look at well-rested people, they're operating at a different level than people trying to get by on 1 or 2 hours less nightly sleep." 
 
 But What Does Your Body Need? 
 
 Of course, what our bodies require and what we give them are two very different things. 
 
 An earlier headline for this post read "Can You Condition Your Body To Get By On Less Sleep?" The answer to that question – and it is, in case you missed it, a very different question than the one now posed – is yes. 
 
 In point of fact, society has been managing on less and less sleep for years. In 2005, a poll conducted by the National Sleep Foundation concluded that Americans averaged just 6.9 hours of sleep per night. According to the report, that's two hours less than people were sleeping on a nightly basis back in the 19th century; an hour drop per night compared to fifty years ago; and 15—25 minutes less per night since the turn of the century. 
 
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 Requirements vary from person to person, so there is, technically speaking, no "right" amount of sleep, but experts say the average adult needs between 7 and 8 hours per night. Babies, 16 hours. Children and teenagers, 10 and 9 hours, respectively. 
 
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 That the typical American is sleeping fewer hours than the minimum recommended average would suggest that many of us are already coping regularly with the side-effects of sleep deprivation. 
 
 What About People Who Function on Four Hours Per Night? 
 
 Margaret Thatcher is said to have averaged about four hours of sleep per night. This means one of two things. 1) The Iron Lady could have been more ferrous still, had she only gotten more sleep, or 2) Thatcher actually owed her political status and leadership style to her indefatigability. 
 
 It's impossible to say now, but it could be that Thatcher belonged to what the Wall Street Journal's Melinda Beck referred to in 2011 as "The Sleepless Elite," a small subset of the population – between 1 and 3% – that functions perfectly fine on less than six hours of sleep a night. Investigations conducted by University of California San Francisco researcher Ying-Hui Fu suggest there could be a genetic basis to lower sleep requirements. When a mutated gene called hDEC2, a variation found in the DNA of short sleepers, was replicated in mice, the animals required less sleep overall and needed less rest to recover from bouts of sleep deprivation. 
 
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 It is safe to say that most of us are not like Margaret Thatcher when it comes to our achievements or our reputations. It is equally safe to say that most of us are not members of "The Sleepless Elite." More likely is that we're simply not aware of how sleepy we really are. 
 
 In the sleep deprivation study led by by Van Dongen, mentioned earlier, test participants who were subjected to consecutive nights of decreased sleep were asked to rate their subjective feelings of sleepiness. Their self-assessments were terrible. While increases in self-rated sleepiness were observed, they were small. After two weeks of sleep deprivation, most volunteers believed themselves to be functioning relatively normally, even though their cognitive and physiological abilities were comparable to those of subjects who had gone days without sleeping whatsoever.
– Got a big day ahead? You're better off thinking you slept well, even if you didn't, a study suggests. Researchers told subjects a normal night of sleep consisted of about 20% to 25% REM sleep. Less than 20%, the subjects heard, meant a worse performance on cognitive tests, while more than 25% meant scoring well on such tests, the Telegraph reports. Researchers duped these subjects into believing that sensors attached to their bodies were tracking their sleep quality. After a night's sleep, some subjects were told they spent 16.2% of the night in REM sleep, while others were informed they'd spent 28.7% of the night in REM. That was all made up, the Smithsonian reports. Next, the subjects took tests involving adding numbers. Subjects who'd been told they'd slept poorly did worse on the tests, reports blogger Eric Horowitz. Those who heard they slept well did better, the Independent reports. In other words, the subjects experienced a "placebo sleep" effect. Indeed, the effect isn't limited to pills: We can get placebo exercise, too, the Smithsonian notes.