After a sleepless night, you likely feel sluggish the next morning, and a small new study suggests why: Your brain cells feel sluggish, too. And when those brain cells are tired, you may be more likely to be forgetful and get distracted more easily, the research found.

In the study, the researchers found that sleep deprivation makes it difficult for brain cells to communicate effectively, which, in turn, can lead to temporary mental lapses that affect memory and visual perception.

In other words, the findings offer clues as to why a sleepless night makes it so hard to think and concentrate the next day.

“We discovered that starving the body of sleep also robs neurons of the ability to function properly,” senior study author Dr. Itzhak Fried, a professor of neurosurgery at the University of California, Los Angeles (UCLA), said in a statement. “This paves the way for cognitive lapses in how we perceive and react to the world around us.”

To study the effects of sleep deprivation, the researchers recruited 12 patients with epilepsy who, as part of a preparation for surgery unrelated to the study, had electrodes implanted into their brains.These electrodes allowed the researchers to monitor hundreds of individual brain cells.

The people in the study then had to stay up for an entire night. During this time, the researchers measured the participants’ brain activity as they carried out certain tasks. For example, the patients were asked to categorize various imagesof faces, places and animalsas fast as possible. Each image caused cells in areas of the brain to produce distinctive patterns of electrical activity. Specifically, the researchers focused on cell activity in the temporal lobe, which regulates visual perception and memory.

The researchers found that as the patients got tired, it became more challenging for them to categorize the images, and their brain cells began to slow down.

“We were fascinated to observe how sleep deprivation dampened brain cell activity,” lead study author Yuval Nir, a sleep researcher at Tel Aviv University in Israel, said in the statement. “Unlike the usual rapid reaction, the neurons responded slowly, fired more weakly and their transmissions dragged on longer than usual.”

In addition, the researchers found that sleep deprivation affects some areas of the brain more than others. Regions of the brain that experienced sluggish brain cell activity also exhibited brain activity normally seen when a person is asleep, the researchers said.

“This phenomenon suggests that select regions of the patients’ brains were dozing, causing mental lapses, while the rest of the brain was awake and running as usual,” Fried said.

In addition, the findings suggest that a lack of sleep can interfere with the ability of neurons in the brain to encode information and translate visual input into conscious thought, the researchers said. For example, when a sleep-deprived driver sees a pedestrian stepping in front of his car, it may take longer for the driver to realize what he or she is seeing because “the very act of seeing the pedestrian slows down in the driver’s overtired brain,” Nir said.

The researchers compared the effects of sleep deprivation to those of drunk driving.

“Inadequate sleep exerts a similar influence on our brain as drinking too much,” Fried said. “Yet no legal or medical standards exist for identifying overtired drivers on the road the same way we target drunk drivers.”

The study was published yesterday (Nov. 6) in the journal Nature Medicine.

Originally published on Live Science.

The Effects of Sleep Deprivation on Your Body

Sleep disorders can make it difficult to get quality sleep at night. They can also increase your risk for the above effects of sleep deprivation on the body.

The following are the most common types of sleep disorders:

  • sleep apnea
  • narcolepsy
  • restless leg syndrome
  • seizures
  • movement disorders

To diagnose these conditions, your doctor may order a sleep study. This is traditionally conducted at a formal sleep center, but now there are options to measure your sleep quality at home, too.

If you’re diagnosed with a sleep disorder, you may be given medication or a device to keep your airways open at night (in the case of sleep apnea) to help combat the symptoms so you can get a better night’s sleep on a regular basis.


The best way to prevent sleep deprivation is to make sure you get adequate sleep. Follow the recommended guidelines for your age group, which is 7 to 9 hours for most adults ages 18 to 64.

Other ways you can get back on track with a healthy sleep schedule include:

  • limiting daytime naps (or avoiding them altogether)
  • refraining from caffeine past noon
  • going to bed at the same time each night
  • waking up at the same time every morning
  • sticking to your bedtime schedule during weekends and holidays
  • spending an hour before bed doing relaxing activities, such as reading, meditating, or taking a bath
  • avoiding heavy meals two hours before bedtime
  • refraining from using electronic devices right before bed
  • exercising regularly, but notin the evening hours close to bedtime

If you continue to have problems sleeping at night and are fighting daytime fatigue, talk to your doctor. They can test for underlying health conditions that might be getting in the way of your sleep schedule.

Keep reading: Tips on improving your sleep.

Many of us have experienced the effects of sleep deprivation: feeling tired and cranky, or finding it hard to concentrate. Sleep is more important for our brains than you may realise.

Although it may appear you’re “switching off” when you fall asleep, the brain is far from inactive. What we know from studying patterns of brain electrical activity is that while you sleep, your brain cycles through two main types of patterns: rapid eye movement (REM) sleep and slow-wave sleep.

Slow-wave sleep, which occurs more at the beginning of the night, is characterised by slow rhythms of electrical activity across large numbers of brain cells (occurring one to four times per second). As the night progresses, we have more and more REM sleep. During REM sleep we often have vivid dreams, and our brains show similar patterns of activity to when we are awake.

Read more: Health Check: three reasons why sleep is important for your health

What are our brains doing while we sleep?

Sleep serves many different functions. One of these is to help us remember experiences we had during the day. REM sleep is thought to be important for emotional memories (for example, memories involving fear) or procedural memory (such as how to ride a bike). On the other hand, slow-wave sleep is thought to reflect the storing of so-called “declarative” memories that are the conscious record of your experiences and what you know (for example, what you had for breakfast).

We also know experiences are “replayed” in the brain during sleep – the memories of these experiences are like segments from a movie that can be rewound and played forward again. Replay occurs in neurons in the hippocampus – a brain region important for memory – and has been best studied in rats learning to navigate a maze. After a navigation exercise, when the rat is resting, its brain replays the path it took through the maze. Replay helps to strengthen the connections between brain cells, and is therefore thought to be important for consolidating memories.

While we’re asleep our brain does a tidy-up, only keeping what it needs. Sashank Saye/Unsplash

But is it that important for you to remember what you had for breakfast? Probably not – that’s why the brain needs to be selective about what it remembers. Sleep allows the brain to sift through memories, forgetting certain things so as to remember what’s important. One way it may do this is by “pruning away” or “scaling down” unwanted connections in the brain.

A leading theory of sleep function – the “synaptic homeostasis hypothesis” – suggests that during sleep there is a widespread weakening of connections (known as “synapses”) throughout the brain.

This is thought to counterbalance the overall strengthening of connections that occurs during learning when we are awake. By pruning away excess connections, sleep effectively “cleans the slate” so we can learn again the next day. Interfering with this scaling down process can, in some cases, lead to more intense (and perhaps unwanted) memories.

The importance of sleep for keeping our brains optimally active may be reflected in our changing sleep patterns as we age. Babies and children sleep much more than adults, probably because their developing brains are learning much more, and being exposed to new situations.

Later in life, sleep declines and becomes more fragmented. This may reflect either a reduced need for sleep (as we are learning less) or a breakdown in sleep processes as we age.

Read more: Children and sleep: How much do they really need?

Sleep is also needed to do a bit of brain “housekeeping”. A recent study in mice found sleep cleanses the brain of toxins that accumulate during waking hours, some of which are linked to neurodegenerative diseases. During sleep, the space between brain cells increases, allowing toxic proteins to be flushed out. It’s possible that by removing these toxins from the brain, sleep may stave off neurodegenerative diseases like Alzheimer’s.

What happens if we have a bad night’s sleep?

Getting enough sleep is important for attention and learning during our waking hours. When we are sleep deprived, we can’t focus on large amounts of information or sustain our attention for long periods. Our reaction times are slowed. We are also less likely to be creative or discover hidden rules when trying to solve a problem.

When you haven’t had enough sleep, your brain may force itself to shut down for a few seconds when you’re awake. During this “micro-sleep” you may become unconscious for a few seconds without knowing it. Drowsiness while driving is a leading cause of motor vehicle accidents, with sleep deprivation affecting the brain just as much as alcohol. Sleep deprivation can also lead to fatal accidents in the workplace – a major issue in shift workers.

Read more: Explainer: how much sleep do we need?

The beneficial effects of sleep on attention and concentration are particularly important for children, who often become hyperactive and disruptive in class when they don’t have enough sleep. One study found getting just one hour less sleep per night over several nights can adversely affect a child’s behaviour in class.

What are the long-term effects?

The longer-term effects of sleep deprivation are more difficult to study in humans for ethical reasons, but chronic sleep disturbances have been linked to brain disorders such as schizophrenia, autism and Alzheimer’s. We don’t know if sleep disturbances are a cause or symptom of these disorders.

Overall, the evidence suggests having healthy sleep patterns is key to having a healthy and well-functioning brain.

Brain Basics: Understanding Sleep


Tracking Sleep Through Smart Technology

Millions of people are using smartphone apps, bedside monitors, and wearable items (including bracelets, smart watches, and headbands) to informally collect and analyze data about their sleep. Smart technology can record sounds and movement during sleep, journal hours slept, and monitor heart beat and respiration. Using a companion app, data from some devices can be synced to a smartphone or tablet, or uploaded to a PC. Other apps and devices make white noise, produce light that stimulates melatonin production, and use gentle vibrations to help us sleep and wake.


Tips for Getting a Good Night’s Sleep

Getting enough sleep is good for your health. Here are a few tips to improve your sleep:

Set a schedule – go to bed and wake up at the same time each day.

Exercise 20 to 30 minutes a day but no later than a few hours before going to bed.

Avoid caffeine and nicotine late in the day and alcoholic drinks before bed.

Relax before bed – try a warm bath, reading, or another relaxing routine.

Create a room for sleep – avoid bright lights and loud sounds, keep the room at a comfortable temperature, and don’t watch TV or have a computer in your bedroom.

Don’t lie in bed awake. If you can’t get to sleep, do something else, like reading or listening to music, until you feel tired.

See a doctor if you have a problem sleeping or if you feel unusually tired during the day. Most sleep disorders can be treated effectively.


Hope Through Research

Scientists continue to learn about the function and regulation of sleep. A key focus of research is to understand the risks involved with being chronically sleep deprived and the relationship between sleep and disease. People who are chronically sleep deprived are more likely to be overweight, have strokes and cardiovascular disease, infections, and certain types of cancer than those who get enough sleep. Sleep disturbances are common among people with age-related neurological disorders such as Alzheimer’s disease and Parkinson’s disease. Many mysteries remain about the association between sleep and these health problems. Does the lack of sleep lead to certain disorders, or do certain diseases cause a lack of sleep? These, and many other questions about sleep, represent the frontier of sleep research.

Where Can I Get More Information?

For information on other neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute’s Brain Resources and Information Network (BRAIN) at:

P.O. Box 5801
Bethesda, MD 20824
(800) 352-9424


Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892
NIH Publication No. 17-3440c

NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient’s medical history.

All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.

John Peever, director of the Systems Neurobiology Laboratory at the University of Toronto, and Brian J. Murray, director of the sleep laboratory at the Sunnybrook Health Sciences Center, respond:

The function of sleep has mystified scientists for thousands of years, but modern research is providing new clues about what it does for both the mind and body. Sleep serves to reenergize the body’s cells, clear waste from the brain, and support learning and memory. It even plays vital roles in regulating mood, appetite and libido.

Sleeping is an integral part of our life, and as research shows, it is incredibly complex. The brain generates two distinct types of sleep—slow-wave sleep (SWS), known as deep sleep, and rapid eye movement (REM), also called dreaming sleep. Most of the sleeping we do is of the SWS variety, characterized by large, slow brain waves, relaxed muscles and slow, deep breathing, which may help the brain and body to recuperate after a long day.

When we fall asleep, the brain does not merely go offline, as implied by the common phrase “out like a light.” Instead a series of highly orchestrated events puts the brain to sleep in stages. Technically sleep starts in the brain areas that produce SWS. Scientists now have concrete evidence that two groups of cells—the ventrolateral preoptic nucleus in the hypothalamus and the parafacial zone in the brain stem—are involved in prompting SWS. When these cells switch on, it triggers a loss of consciousness.

After SWS, REM sleep begins. This mode is bizarre: a dreamer’s brain becomes highly active while the body’s muscles are paralyzed, and breathing and heart rate become erratic. The purpose of REM sleep remains a biological mystery, despite our growing understanding of its biochemistry and neurobiology.

We do know that a small group of cells in the brain stem, called the subcoeruleus nucleus, controls REM sleep. When these cells become injured or diseased, people do not experience the muscle paralysis associated with REM sleep, which can lead to REM sleep behavior disorder—a serious condition in which the afflicted violently act out their dreams.

Here’s Why You Can’t Think Straight When You’re Sleep Deprived

After a bad night of sleep, we all typically feel distracted and off our mental game. But do you really know all the ways a lack of sleep interferes with your cognitive performance? Most of my patients are surprised to learn just how broadly a lack of sleep affects their ability to think at their best.

It’s difficult to identify a cognitive skill that isn’t affected by sleep, and compromised by sleep deprivation. That’s how pervasive the effects of not-enough sleep are on the brain.

Thanks to recent research, we now know that sleep deprivation interferes with brain function at a cellular level. A study by scientists at UCLA found that sleep deprivation interferes with the ability of some brain cells to function and communicate with one another. We’ve got billions of neural cells working on our behalf, enabling us make decisions, process information, focus on important information—and remember it down the road. Sleep deprivation slows that work down, compromising our mental performance.

Less robust brain-cell activity isn’t the only way poor sleep hampers the brain, and our ability to think. Other recent scientific discoveries have told us more about how lack of sleep changes brain function, and cognitive performance. Sleep deprivation:

  • Disrupts levels of hormones, including serotonin, dopamine, and cortisol, that affect thought, mood, and energy
  • Leaves key areas of the brain in an “always on” state of activation
  • Activates genes that interfere with optimal brain activity. (Because genetic make-up is different from one person to the next, the effects of sleep deprivation on brain function can be, as well— so, some people will experience the negative cognitive and mood effects of sleep deprivation more than others.)

We’ve still got much to learn about the full effects of poor and insufficient sleep on cognitive performance and health. But as you’re about to see, what we know already offers many compelling reasons to make getting plenty of sleep a top priority.

You can’t focus well

Attention is especially sensitive to the effects of sleep deprivation. You know this through experience, when you have trouble focusing on tasks after a night of poor sleep. Unfortunately, “a night of poor sleep” is often a series of nights of poor sleep, leading to chronic sleep debt and continually compromised attention.

New research suggests that as many as 75 percent of people with ADHD, attention deficit hyperactivity disorder, may have a chronic, underlying sleep problem stemming from a disruption to their circadian rhythms. (I’ll be talking more in depth about the relationship between sleep and ADHD, soon.)

Attention is about focus and concentration—your ability to stay with tasks long enough to make meaningful progress. For most of us, focus is key to both our performance and our sense of purpose, in and away from work. Sleep deprivation makes focus harder to achieve.

Your reaction time slows down

Attention isn’t only about focus on big, thoughtful tasks. It’s also about focusing on—and making sense of—what’s important right now. Remember those sluggish brain cells that result from being sleep deprived? Scientists in that recent study found that sleep deprivation slowed down neural cells’ ability to absorb visual information and translate that visual data into conscious thought. Research shows reaction times are dulled as much by sleeplessness as they are by alcohol.

Reacting to changing circumstances around us is a critical skill that helps keep us—and others—safe. And it can be significantly compromised by sleep deprivation.

You have trouble making—and storing—memories

I talked recently about the links between sleep problems and Alzheimer’s disease. Now, we have brand-new research showing just how important sleep during middle age can be to memory and cognitive health in later years. A new study found that disrupted sleep during middle age, including insomnia, is connected to cognitive decline a decade or more later. It isn’t just sleeping too little during middle age the raises risks for cognitive decline later on—the study found sleeping 9 or more hours a night was also associated with later-in-life cognitive problems.

We know sleep is deeply critical to memory in all its phases—from acquiring memories, to storing them, to recalling them. All phases of memory are complex and involve multiple areas of the brain that are affected by lack of sleep.

Sleep deprivation impairs learning and the ability to create new memories. Poor sleep also diminishes your capacity to recall memories you’ve already made, whether you made them a month ago, or 10 years ago. That’s why, when you’re short on sleep, you’re more apt to forget the name of your high-school crush, or one of those many passwords you need to keep track of.

Both memory acquisition and memory recall take place, of course, when you’re awake. It’s the middle stage of memory—known as consolidation—that actually happens when you’re sleeping. Memory consolidation is the brain’s process of storing new memories for long-term retrieval. It’s a complex, multi-phase process, and it’s one part of the important work the brain undertakes while you’re snoozing.

The work of memory consolidation has at least a couple of key purposes:

  • It stabilizes and stores memories for retrieval later
  • It frees up bandwidth in the brain to tackle the next day’s work of acquisition—making new memories through learning and exposure to stimuli

Several stages of sleep—including both deep, slow-wave sleep and REM sleep—are important to memory consolidation. And new research provides more evidence that multiple stages of non-REM sleep–when the brain generates bursts of electrical activity known as sleep spindles—are also critical to our ability to store memories and recall them later.

Bottom line: if you shortchange yourself on sleep, and deprive yourself of the 4-5 sleep cycles that a full night’s rest provides, you risk compromising your memory. That matters to your performance tomorrow—and to your memory and cognitive health down the road.

Your decision making and judgment skills suffer

The prefrontal cortex—the area of the brain that handles planning and complex decision making, and enables you to make complicated, nuanced judgment calls that balance risk and reward—is especially hard hit by sleep deprivation. Low on sleep, you’re more likely to be impulsive in your decision making. Impulsive decisions tend to favor immediate rewards, rather than the best outcomes over time. You’re also more likely to engage in risky behavior, according to research. The self-control that the prefrontal cortex enables us to exert becomes diminished when we’re sleep deprived, and that can have consequences on everything from your relationships to your health to your finances.

Recent research showed the impact of moderate, chronic sleep deprivation on financial decision making. Two groups of sleepers—of 5 and 8 hours a night—were given a choice, repeated daily for a week: they could take a certain amount of money guaranteed, or take a risk on receiving a higher sum of money—with the risk of getting nothing at all. Over the course of the week, the 5-hour-a-night, sleep-deprived participants increasingly gravitated toward the riskier option. Especially interesting and important was this detail: As their decision-making grew riskier, the sleep-deprived subjects were unable to perceive that change happening in themselves. This suggests not only will sleep deprivation make us less adept at sound decision making—but we won’t have the self-awareness to catch ourselves making shaky decisions as they happen.

There’s also fascinating research indicating that sleep deprivation makes us more likely to cheat—again, that’s thanks, researchers think, to the depletion of our ability to exert self-control in favor of doing the right, but often harder, thing.

Sound judgment, solid planning, thoughtful decision-making—these are the bedrock cognitive skills that help us thrive, succeed at work and in relationships, create stable, prosperous lives, and help us live out our ethical values. Sleep deprivation makes these important, grown-up life skills more difficult.

You’re less creative

The science on how sleep affects creativity is really interesting. When we’re distracted, unfocused, and fatigued—just when our other cognitive abilities are struggling—creativity perks up. Anyone who’s struggled to come up with an inspired solution—whether it’s a design issue at work or the perfect birthday gift for your mother-in-law—only to have the answer present itself just as you’re falling asleep, knows how mysterious our creative thinking can be. These are what I call “moments of groggy greatness,” when our mental fatigue opens up pathways of innovative thinking, and they happen to all of us.

Does this mean going without sleep boosts creativity? No! Very much to the contrary. REM sleep in particular appears to be especially important to creative thinking and inspiration. (Remember, REM is the time when we dream most actively and vividly.) You get REM in segments throughout the night, each time you move through a complete sleep cycle. But, periods of REM become longer as the night progresses, and your heaviest doses of REM occur in the last third of a night’s sleep. If you shortchange your sleep time, you risk missing out on the creativity-boosting effects of REM.

Rather than depriving yourself of sleep, pay attention to the times of day when you’re a little on the groggy side. For most people, that’s first thing in the morning and near the end of the day. Let your brain roam during these times, and see what surprising, innovative ideas spring to mind.

Women multi-task more—and that takes more energy, and more sleep

Science tells us: women are more robust multitaskers than men are. Women’s ability to handle bunch of thought projects at once means their brains expend more energy than men’s—and that means they need more sleep, according to recent research. Scientists found women’s multitasking brains need an average of about 20 additional minutes of sleep a night. It’s not just multitasking where men’s and women’s brains differ in their needs for sleep—and the effects of sleep deprivation. I led a study a few years ago that looked at the mental and physical effects of insufficient sleep on men and women. Among other interesting results, we found women who are sleep deprived experience greater degrees of anger, hostility, and depression early in the morning.

I’ll talk more soon about the emotional consequences of sleep deprivation. The effects are just as complex, and just as important to your performance and quality of life.

Sweet Dreams,
Michael J. Breus, PhD, DABSM
The Sleep Doctor™

What Happens To Your Brain When You Don’t Get Enough Sleep

There are many things you can do to achieve better sleep. An important one is to get more time in the sun to encourage the body’s production of melatonin, otherwise known as the sleep hormone. You might not think it’s important if you don’t get enough sleep every night, but this can be really bad for your brain. Research has found that just one night without sleep can have a huge impact on your wellbeing, and not just because you feel tired and lack energy.

In a study from UC Berkeley’s Sleep and Neuroimaging Laboratory, 26 people were divided into two groups. One group stayed up for 35 hours, and the other slept normally. Then, both groups were shown horrific images, such as of mutilated bodies, before their brain activity was measured. The results found that the amygdala, the part of the brain that controls the “flight or flight” response, is boosted when people don’t get enough sleep, which means that logical reasoning takes a backseat. And that’s just from one night of no sleep! Here are other things that happen to your brain from a lack of vital sleep.

Your Brain Slows Down

An American study found that sleep deprivation actually disrupts the brain cells’ ability to communicate with each other. This explains why you might find it difficult to concentrate or remember things when you haven’t had a good night’s sleep. Instead of having quick communication, brain neurons respond slower and weaker.

Your Brain Gets Damaged

An Italian study of mice found that not getting enough sleep can harm your brain. The researchers divided mice into four groups. One group slept for six to eight hours, another was woken up throughout their sleep, the third group of mice was kept awake for eight hours, and the fourth group was forced to stay awake for five days in a row. What the researchers found was that when they compared brain activity of the mice in different groups, the mice who were sleep-deprived experienced sustained microglia activation. This is an inflammatory response that is tied to brain pathology such as neurodegenerative diseases.

You Battle To Control Your Anger

A study published in the Telegraph found that when people were sleep deprived, the connection between the medial prefrontal cortex and amygdala in the brain was disturbed. This meant that people lacked the ability to regulate their emotions, causing heightened feelings of anger. If you consider that up to 40 percent of people experience insomnia, this could explain why there are so many angry people on our roads and in our lives.

You Risk A Mental Disorder

Interestingly, when you don’t have enough sleep for one night, you might have symptoms of mania, such as a boost to your mood because your brain’s released hormones to keep you awake. However, soon your mood will crash, leading to depression symptoms. Lack of sleep over time is tied to depression, as some studies have confirmed that people who survive on less than six hours of sleep at night are likely to suffer from this mental disorder.

Your Hormones Are Disrupted, Causing Weight Gain

If you don’t get enough sleep, your body’s ghrelin hormones which are known to stimulate feelings of hunger, increase by up to 15 percent, according to a Stanford University study. This hormonal release, some of which comes from the brain, can make you pile on the weight, fast – sometimes up to 2.2. pounds in one week!
Getting enough sleep is important for your energy levels, but it really helps your brain to function optimally. When you don’t get enough sleep, your brain slows down and its functions are disrupted, which can lead to a range of problems. Encourage healthier sleeping habits, such as by getting more sun and finding ways to cut stress from your life, so that you get the quality of sleep your brain so desperately craves.

Your brain can’t catch a break. Long after your major muscles have drifted off to dreamland, the tissue between your ears is still hard at work finding ways to keep you healthy and happy. Wonder what happens in your head while the rest of you relaxes? Check out the contributions your brain makes during those after-dark hours.

It Powers Your Dreams

When you’re awake, a small structure in the brain called the thalamus relays sensory signals to the cerebral cortex, allowing you to perceive small changes in your environment. It typically goes offline during sleep (that’s why you can tune out the sound of, say, a flushing toilet or barking dog), but during REM sleep, the thalamus reengages, sending images and sounds to your cortex which become part of your dreams. ,

It Relaxes You

Even among people who have vivid dreams at night, it’s rare to sleepwalk or physically move from the bed. That’s partially due to the brain stem, located at the base of the brain, which sends out muscle-relaxing signals that temporarily paralyze the limbs to keep them from engaging during the night.

It Boosts Memory

Memories and newly learned skills, like playing the piano, are moved to more permanent regions of the brain while you sleep, making them easier to recall going forward. Whether you’re studying for a test or simply need to remember your to-do list tomorrow, a good night’s sleep will help.

It Protects Against Illness

Waste products linked to health conditions such as Alzheimer’s disease build up in the brain throughout the day. At night, your body produces an increased amount of a clear liquid called cerebrospinal fluid. This liquid moves through the brain, helping to flush out toxins that could potentially contribute to harmful diseases.

Even though the brain remains active when you’re asleep, it takes time for it to complete the various tasks that keep you healthy. The brain thrives on a consistent sleep schedule, so aim for the recommended seven to eight hours each night.

It’s no surprise that a night without enough Zzzs can lead to a groggy morning. But bleary eyes and gaping yawns aren’t the only things that can happen when your body needs more shut-eye.

Indeed, there are more nightmarish side effects to sleep deprivation.

If a person is deprived of sleep, it can lead to “tremendous emotional problems,” said Dr. Steven Feinsilver, the director of the Center for Sleep Medicine at Icahn School of Medicine at Mount Sinai in New York City. “Sleep deprivation has been used as a form of torture,” he said.

There isn’t a clear definition of exactly how long a person must go without sleep, or how little sleep a person has to get to be considered sleep-deprived, and different people need different amounts of sleep, so there may be no universal definition of “sleep deprivation.” Rather, a person is considered sleep-deprived if they get less sleep than they need to feel awake and alert, researchers say.

But still, research over the years has shown that people can be physically and psychologically damaged from not getting enough sleep, said David Dinges, a professor of psychology and the director of the Unit for Experimental Psychiatry at the University of Pennsylvania.

In fact, the damage is so apparent that it is unethical to coercively deprive someone of sleep, Dinges said. In the studies of sleep deprivation that Dinges and his colleagues conduct in their lab, healthy volunteers are placed in medically safe environments and constantly monitored.

But studying sleep deprivation is important, according to these researchers and others who study the condition. They say that learning what happens in people who are deprived of sleep can help researchers better understand the function of sleep and its importance for both physical and emotional health.

Emotions askew

The problems can start on a somewhat minor scale.

“Clearly, your brain doesn’t work very well when you’re sleep-deprived,” Feinsilver said. Even a low level of sleep deprivation has an impact on cognitive and emotional function, he said.

Dinges explained that some of the first emotional impacts of sleep deprivation involve positive emotions. “When people get sleep-deprived, they don’t show positive emotion in their faces,” Dinges said. A sleep-deprived person may say they’re happy, but they still have a neutral face, he said.

And they won’t recognize other people as happy, either. A positive look on someone’s face can appear neutral to a sleep-deprived person, and neutral look is often interpreted as a negative look, Dinges said. The sleep-deprived brain may not be as capable of detecting positive emotions as a more rested brain, he said.

And sleep-deprived people also don’t tolerate disappointment very well, Dinges added.


As little as a single night of sleep deprivation can result in a person having a phenomenon called “microsleeps,” the next day, Feinsilver said.

A person begins to fall into mini-snooze sessions, which last up to 30 seconds. Some people’s eyes remain open during microsleeps, but the disturbing thing about microsleeps is that during sleep, the person is essentially blind, even if their eyes are open, Feinsilver said. They’re not processing information, he said.

Studies show that during microsleeps, the brain goes into a sleep state rapidly and uncontrollably, Dinges said. People can force themselves awake, but they will soon fall into another microsleep, he said.

Both Dinges and Feinsilver said that this condition can be incredibly dangerous, especially if you’re behind the wheel.


People often say they feel loopy after a night of no sleep. But in more extreme cases, losing sleep may cause delirium.

True delirium occurs when a person becomes completely disoriented, Feinsilver said. “Sleep can play a role in that,” he said.

Patients who have been hospitalized in intensive care units — where lights and sounds may continue all day and night — can develop a condition that doctors call “ICU delirium,” he said. And while it’s unclear if sleep deprivation is the cause of this delirium, doctors do think that loss of sleep is one reason people in the hospital for extended periods develop bizarre behavior, he said.

The worst thing you can do for sleep is put someone is a hospital, Feinsilver added. It’s fairly common for for hospitalized patients to develop insomnia, he said.


Seeing things that aren’t there can be a side effect of chronic sleep deprivation, but whether sleep deprivations can induce true hallucinations may be up for debate.

Feinsilver said he personally experienced hallucinations due to sleep deprivation, in October of his first year out of medical school. A newly minted medical resident, Feinsilver said he had been chronically sleep-deprived for several months.

“I it was October, because I was in the ICU after a night on call,” and there was pumpkin by the nurses’ station, he said. “I had a very vivid feeling of the pumpkin talking to me,” he said.

But Dinges was more skeptical about hallucinations.

“There’s no question that misperceptions can occur,” Dinges said. When people are very sleepy and performing a task, they may see something flicker in their peripheral vision, or they may think they see blinking lights, but not be sure, he said. All of these are indications that the brain isn’t interpreting information clearly, he said.

Can you die of sleep deprivation?

In a famous series of animal experiments, researcher found that total sleep deprivation could kill lab rats.

In 2012, a Chinese man reportedly died after going 11 days without sleep. However, it’s unlikely that lack of sleep alone caused his death (other factors likely played a role, such as drinking and smoking).

Of course, studying this phenomenon in humans is difficult – even when you put aside the clear ethical dilemmas.

“Can you die of sleep deprivation? It’s not easy,” Feinsilver said. “Because you’ll fall asleep,” he added.

Dinges agreed.

“I don’t believe that people can keep themselves awake until they succumb to death,” because the drive to sleep turns on, and then continues to turn on, he said. “You can’t will yourself to stay awake that long,” he said.

Still, there’s no question that sleep deprivation has “serious adverse health effects,” Dinges said.

“Everything we know about sleep loss is harmful,” he said. But — on a more positive note — most of the effects of sleep deprivation dissipate after you sleep, he added.

Follow Sara G. Miller on Twitter @SaraGMiller. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

LETTER: Team No Sleep, just because you don’t want to sleep doesn’t mean I don’t want to

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126 Shares Barcadere, a more or less sleepy community in Vieux-Fort has been woken up recently, with the opening of a new entertainment lounge late last year.

The area has come alive with excitement: music, dance, drinks and general partying every week, and the occasional street jam takes things to another level.

This new venture has no doubt come at a cost to the proprietors, and residents as well. Staff, fans and partygoers revel all night with no sleep. They don’t sleep and neither do you.

Residents of the densely populated Barcadere area, now literally endure sleepless nights 3-4 times a week every week. Partying starts from evening and ends in the early morning, but not early enough.

Loud music from speakers usually placed outside the establishment, DJ’s creating excitement and partygoers screaming and chanting lyrics has become disturbing nuisances to us residents.

Some residents who have made complaints, report that they have been met with angry opposition and are labeled as jealous haters. I won’t doubt that indeed some hatred has grown but it’s not because of jealousy, but because you’re preventing the people from sleeping.

Residents, including myself, literally struggle to fall asleep and when we happen to sleep we will be woken. It’s more like a movement, Team No Sleep: no sleep for anybody. I don’t want to sleep and neither should you.

We are literally blasted with loud music on a regular basis, creating annoyance and keeping you from getting a good night sleep. Not only is it loud to begin with but after 1:00 am, as if going for their last lap, this band of excitement shoots up the volume and the exuberant DJ’s can be heard exciting his crowd over the microphone, literally startling you and causing you to awake and not fall asleep again, if you happened to fall asleep in the first place that is.

To add to the nuisance, the music goes on pass the supposed cut off time. There was an occasion when the music went on as late as 4:00 am; admittedly on that day it was much lower by then. As a matter of fact the music never cuts off on time. On occasions after calling the police after cut-off time, the music will then be abruptly turned off moments after.

Speaking of the police, they have the most disgraceful disposition, when called to complain about the noise levels. One officer even had the audacity to tell me to be considerate, it is the weekend and people are enjoying themselves — when I called them one morning at 2:32 am.

Be considerate? Interesting words. Who is being considerate of us residents? What about me: the student who has school in the morning and in the middle of exams; or the working man who has to wake up early to go to work next morning; or the elderly lady living across the street, or the terminally ill folks in the vicinity? Who is considering us?Isn’t that the job of the police, Mr. Officer?

This situation has become a great annoyance to residents of the Barcadere and as it disrupts our sleep on a regular basis. Some residents have taken the steps to voice their complaints but report that family quarrels, saying they’re just jealous.

From where I stand jealous hatred is the last thing on our minds. In fact some of us, including myself, were happy for your progress and the brand you’re building for yourself. So please, get over yourself.

As residents of the area we aren’t jealousy hating on the progress of our ‘native son and brother’ we just want to sleep and to not be disturbed in our homes night after night. Consider that, consider others and the residential area you’re in and lower the volume, keep your speakers inside your club, host your street parties in non-residential areas and cut off when you’re supposed to; all these will maintain the unity in the neighbourhood and finally return some sleep.

So please Team No Sleep, just because you don’t want to sleep, doesn’t mean we don’t want to. I for sure would like to sleep thank you.

– Resident of the Barcadere


Lack of sleep is not necessarily fatal for flies

Male flies kept awake do not die earlier than those allowed to sleep, leading researchers to question whether sleep is essential for staying alive.

The team behind the research, from Imperial College London, suggest that for flies sleep may not perform a vital biological function in the way that food does.

While we know the biological underpinnings of food – we need to take in calories in order to fuel our cells – the same is not true for sleep. Sleep deprivation is known to cause severe problems with cognition, memory, attention and reflexes, for example, but it is not clear whether lack of sleep alone actually causes animals to die.

It’s not that there are no consequences to not sleeping, but our study has made us question whether sleep deprivation alone causes death Dr Giorgio Gilestro

Previous experiments have shown that some animals die when deprived of sleep, but the studies are unclear about exactly why this is. The researchers behind the new study suggest that the way the experiments were run could mean the animals died of stress due to the methods of keeping them awake.

Now, in experiments with several thousand fruit flies, the researchers have shown that male flies denied sleep do not die earlier than those who have regular sleep. Their results, published today in Science Advances, show that female flies die on average three days earlier out of a 40-50-day average lifespan.

In an initial study monitoring average sleep duration of flies, the team found some individuals that naturally slept for as little as 5-15 minutes per day, compared to a normal range of several hours a day.

Dr Giorgio Gilestro, from the Department of Life Sciences at Imperial, said: “One of the reasons sleep is considered essential for life is that all animals sleep, so we were surprised to find some flies that needed so little. We wanted to find out if this was just a peculiarity for a lucky few flies, or whether it was something any fly could do.”

Not as vital as food

To keep the flies awake, the researchers kept each fly in a tube linked to an automatic monitoring system. If the system detected no movement for 20 seconds, then the tube rotated, waking the fly up.

This system allowed the team to experiment with hundreds of flies at once, giving them a better understanding of the average response to sleep deprivation. They found that male flies did not die younger when starved of sleep, and female flies died on average only slightly younger.

The flies could still have been snatching some sleep, building up micro-sleeps in the 20 seconds before the tube turned, or even sleepwalking, but they would be unlikely to get much quality sleep this way.

While the current study was in flies, the team speculate that if sleep is not essential for life in the same way food is, then it is possible that their results could apply across the animal kingdom, including in humans.

Dr Gilestro said: “For food, we have calories that are ‘vital’ to keep us alive and calories that are ‘useful’ to help us function well. It might be that sleep is only ‘useful’: it would still be difficult for us to function without it, but not necessarily fatal.”

No ‘sleep debt’ for the deprived

The researchers say that while male flies did not die earlier without sleep under lab conditions, in the wild lack of sleep would cause knock-on effects that would put them at greater risk from predators or competition.

Dr Gilestro added: “Lack of sleep could make it hard for them to function properly and safely, just as a lack of sleep might cause a sleep-deprived human to crash their car.

“It’s not that there are no consequences to not sleeping – in fact we will be investigating the effects on mental performance in flies in future experiments – but our study has made us question whether sleep deprivation alone causes death.”

During their experiments, the team also found that even while sleep deprived, the flies followed ‘normal’ patterns of activity. Flies are usually more active at dawn and dusk, and even when they hadn’t had any sleep for many days in a row, this was still the case.

The researchers say this shows that the flies are not building up a ‘sleep debt’ – they do not necessarily get sleepier the longer they stay awake, but keep to relatively normal patterns of activity. This suggests the pressure to sleep is controlled more strongly by the time of day than by the amount of sleep taken.

This was further shown when flies that had been deprived were allowed to sleep again. They slept a little longer for a day or two but returned to normal patterns quickly, instead of immediately catching up on all the sleep they had lost with one extremely long sleep.

‘Most sleep does not serve a vital function. Evidence from Drosophila melanogaster’ by Quentin Geissmann, Esteban J. Beckwith, and Giorgio F. Gilestro is published in Science Advances.

See the press release of this article

Sleep and brain function

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