Why Do We Need Sleep?

While the brain sleeps, it clears out harmful toxins, a process that may reduce the risk of Alzheimer's, researchers say.

During sleep, the flow of cerebrospinal fluid in the brain increases dramatically, washing away harmful waste proteins that build up between brain cells during waking hours, a study of mice found.

"It's like a dishwasher," says Dr. Maiken Nedergaard, a professor of neurosurgery at the University of Rochester and an author of the study in Science.

The results appear to offer the best explanation yet of why animals and people need sleep. If this proves to be true in humans as well, it could help explain a mysterious association between sleep disorders and brain diseases, including Alzheimer's.

Nedergaard and a team of scientists discovered the cleaning process while studying the brains of sleeping mice.

The scientists noticed that during sleep, the system that circulates the cerebrospinal fluid through the brain and nervous system was "pumping fluid into the brain and removing fluid from the brain in a very rapid pace," Nedergaard says.

The team discovered that this increased flow was possible in part because when mice went to sleep, their brain cells actually shrank, making it easier for fluid to circulate. When an animal woke up, the brain cells enlarged again and the flow between cells slowed to a trickle. "It's almost like opening and closing a faucet," Nedergaard says. "It's that dramatic."

Nedergaard's team, which is funded by the National Institute of Neurological Disorders and Stroke, had previously shown that this fluid was carrying away waste products that build up in the spaces between brain cells.

The process is important because what's getting washed away during sleep are waste proteins that are toxic to brain cells, Nedergaard says. This could explain why we don't think clearly after a sleepless night and why a prolonged lack of sleep can actually kill an animal or a person, she says.

So why doesn't the brain do this sort of housekeeping all the time? Nedergaard thinks it's because cleaning takes a lot of energy. "It's probably not possible for the brain to both clean itself and at the same time (be) aware of the surroundings and talk and move and so on," she says.

The brain-cleaning process has been observed in rats and baboons, but not yet in humans, Nedergaard says. Even so, it could offer a new way of understanding human brain diseases including Alzheimer's. That's because one of the waste products removed from the brain during sleep is beta amyloid, the substance that forms sticky plaques associated with the disease.

That's probably not a coincidence, Nedergaard says. "Isn't it interesting that Alzheimer's and all other diseases associated with dementia, they are linked to sleep disorders," she says.

Researchers who study Alzheimer's say Nedergaard's research could help explain a number of recent findings related to sleep. One of these involves how sleep affects levels of beta amyloid, says Randall Bateman, a professor of neurology at Washington University in St. Louis who wasn't involved in the study.

"Beta amyloid concentrations continue to increase while a person is awake," Bateman says. "And then after people go to sleep that concentration of beta amyloid decreases. This report provides a beautiful mechanism by which this may be happening."

The report also offers a tantalizing hint of a new approach to Alzheimer's prevention, Bateman says. "It does raise the possibility that one might be able to actually control sleep in a way to improve the clearance of beta amyloid and help prevent amyloidosis that we think can lead to Alzheimer's disease."

The Moon and Your Sleep

We are all, quite literally, lunatics—and I mean that in the nicest way possible. It is the moon, after all, that is responsible for the luna part of that word—and the moon has always made us at least a little crazy. Over our long history we have been charmed by it, spooked by it, seduced by it. We kiss by the moon, go to war by the moon, we spent $25 billion—in 1960s money, no less—to go to the moon. So it’s hardly a surprise that the moon is in some very real ways inside of us all.

The human menstrual cycle is the best-known example of the way our bodies—over millions of years of evolution—have synchronized themselves to the rhythms of the moon. Less well-known is the lunar link to the electrochemistry of the brain in epileptic patients, which changes in the few days surrounding a new moon, making seizures more likely. And then there are the anecdotal accounts of the effects the moon has on sleep

People have long reported that it is harder to get to sleep and remain asleep when the moon is full, and even after a seemingly good night’s rest, there can be a faint sluggishness—a sort of full-moon hangover—that is not present on other days. If you’re sleeping on the prairie or in a settler’s cabin with no shades, the simple presence of moonlight is an inescapable explanation. But long after humans moved indoors into fully curtained and climate-controlled homes, the phenomenon has remained. What’s never been clear is whether it’s the real deal—if the moon really does mess with us–or if it’s some combination of imagination and selective reporting, with people who believe in lunar cycles seeing patterns where none exist. Now, a report in the journal Current Biology suggests that the believers have been right all along.

For a research paper that was just released today, the initial work took place an awful long time ago. In 2000, a team of investigators from the University of Basel, the Swiss Federal Institute of Technology and the Switzerland Centre for Sleep Medicine, recruited 33 volunteers and studied them in a sleep lab on and off over the course of three years. The investigators gathered a range of data—brain wave activity during sleep as measured by electroencephalograms (EEG); levels of melatonin, a sleep-related hormone; the amount of time it took subjects to fall asleep and the amount of time they spent in deep sleep; and their subjective reports of how rested they felt the next day. All of it was intended to learn more about human sleep patterns in a general way and, more specifically, how they are affected by age and gender. Only a decade later did the investigators realize that they may be able to re-crunch the data to learn about the moon.

“The aim of exploring the influence of different lunar phases on sleep regulation was never a priori hypothesized,” they wrote in a wonderfully candid passage in their paper. “We just thought of it after a drink in a local bar one evening at full moon.”

Thus should all great science be done, since as it turned out, the second look revealed intriguing patterns. On average, the subjects in the study took five minutes longer to fall asleep on the three or four nights surrounding a full moon and they slept for 20 fewer minutes. In addition, EEG activity related to deep sleep fell 30%, melatonin levels were lower and the subjects reported feeling less refreshed the next day than on other days. The subjects slept in a completely darkened lab with no sight of the moon, and none of them—at least from what was known—appeared to have given any thought at all to lunar cycles. And since the moon was not an experimental variable in the original study, it was never mentioned either to the subjects or even among the investigators.

In terms of scientific reliability, all of this is both good and not so good. A study can’t get more effectively double-blind than if no one is even thinking about the thing you wind up testing for, which makes the findings uniquely objective. On the other hand, the ideal moon study would have been carefully set up to give equal weight to every night in the lunar cycle. This study—while capturing most of the nights in the month—did so in a less rigorous way.

“The a posteriori analysis is a strength and a weakness,” concedes lead author Christian Cajochen, head of the University of Basel’s Centre for Chronobiology, in an e-mail to TIME. “The strength is that investigators and subject expectations are not likely to influence the results, yet the weakness is that each subject was not studied across all lunar phases.”

Even if the moon has as significant an effect on sleep as the study suggests, what’s less clear is the mechanism behind it. Dark labs eliminate the variable of light, so that can’t be it. And before you ask, no, it’s not gravity either. The authors stress that while lunar gravity does indeed raise tides in the oceans, it doesn’t on lakes and even many seas. Those bodies are simply too small to feel the effects—to say nothing of human bodies.

Rather, the answer is simply that we, like every other species on Earth, evolved on a particular planet with a particular set of astronomical cycles—day and night, full moons and less full—and our circadian systems adapted. It’s hard to say where the internal clock is in, say, a flowering plant, but in humans, it’s likely in the suprachiasmatic nuclei, a tiny region of the brain near the optic nerve involved in the production of melatonin, certain neurotransmitters and other time-keeping chemicals, all in a rhythm consistent with both its terrestrial and cosmic surroundings. Physically, human beings may be creatures of just this world, but our brains—and our behavior—appear to belong to two.

Read more

Do You Have ADHD Or Sleep Deprivation?

Diagnosing the Wrong Deficit

IN the spring of 2010, a new patient came to see me to find out if he had attention-deficit hyperactivity disorder. He had all the classic symptoms: procrastination, forgetfulness, a propensity to lose things and, of course, the inability to pay attention consistently. But one thing was unusual. His symptoms had started only two years earlier, when he was 31.

Though I treat a lot of adults for attention-deficit hyperactivity disorder, the presentation of this case was a violation of an important diagnostic criterion: symptoms must date back to childhood. It turned out he first started having these problems the month he began his most recent job, one that required him to rise at 5 a.m., despite the fact that he was a night owl.

The patient didn’t have A.D.H.D., I realized, but a chronic sleep deficit. I suggested some techniques to help him fall asleep at night, like relaxing for 90 minutes before getting in bed at 10 p.m. If necessary, he could take a small amount of melatonin. When he returned to see me two weeks later, his symptoms were almost gone. I suggested he call if they recurred. I never heard from him again.

Many theories are thrown around to explain the rise in the diagnosis and treatment of A.D.H.D. in children and adults. According to the Centers for Disease Control and Prevention, 11 percent of school-age children have now received a diagnosis of the condition. I don’t doubt that many people do, in fact, have A.D.H.D.; I regularly diagnose and treat it in adults. But what if a substantial proportion of cases are really sleep disorders in disguise?

For some people — especially children — sleep deprivation does not necessarily cause lethargy; instead they become hyperactive and unfocused. Researchers and reporters are increasingly seeing connections between dysfunctional sleep and what looks like A.D.H.D., but those links are taking a long time to be understood by parents and doctors.

We all get less sleep than we used to. The number of adults who reported sleeping fewer than seven hours each night went from some 2 percent in 1960 to more than 35 percent in 2011. Sleep is even more crucial for children, who need delta sleep — the deep, rejuvenating, slow-wave kind — for proper growth and development. Yet today’s youngsters sleep more than an hour less than they did a hundred years ago. And for all ages, contemporary daytime activities — marked by nonstop 14-hour schedules and inescapable melatonin-inhibiting iDevices — often impair sleep. It might just be a coincidence, but this sleep-restricting lifestyle began getting more extreme in the 1990s, the decade with the explosion in A.D.H.D. diagnoses.

A number of studies have shown that a huge proportion of children with an A.D.H.D. diagnosis also have sleep-disordered breathing like apnea or snoring, restless leg syndrome or non-restorative sleep, in which delta sleep is frequently interrupted.

One study, published in 2004 in the journal Sleep, looked at 34 children with A.D.H.D. Every one of them showed a deficit of delta sleep, compared with only a handful of the 32 control subjects.

A 2006 study in the journal Pediatrics showed something similar, from the perspective of a surgery clinic. This study included 105 children between ages 5 and 12. Seventy-eight of them were scheduled to have their tonsils removed because they had problems breathing in their sleep, while 27 children scheduled for other operations served as a control group. Researchers measured the participants’ sleep patterns and tested for hyperactivity and inattentiveness, consistent with standard protocols for validating an A.D.H.D. diagnosis.

Of the 78 children getting the tonsillectomies, 28 percent were found to have A.D.H.D., compared with only 7 percent of the control group.

Even more stunning was what the study’s authors found a year after the surgeries, when they followed up with the children. A full half of the original A.D.H.D. group who received tonsillectomies — 11 of 22 children — no longer met the criteria for the condition. In other words, what had appeared to be A.D.H.D. had been resolved by treating a sleeping problem.

But it’s also possible that A.D.H.D.-like symptoms can persist even after a sleeping problem is resolved. Consider a long-term study of more than 11,000 children in Britain published last year, also in Pediatrics. Mothers were asked about symptoms of sleep-disordered breathing in their infants when they were 6 months old. Then, when the children were 4 and 7 years old, the mothers completed a behavioral questionnaire to gauge their children’s levels of inattention, hyperactivity, anxiety, depression and problems with peers, conduct and social skills.

The study found that children who suffered from sleep-disordered breathing in infancy were more likely to have behavioral difficulties later in life — they were 20 to 60 percent more likely to have behavioral problems at age 4, and 40 to 100 percent more likely to have such problems at age 7. Interestingly, these problems occurred even if the disordered breathing had abated, implying that an infant breathing problem might cause some kind of potentially irreversible neurological injury.

CLEARLY there is more going on in the nocturnal lives of our children than any of us have realized. Typically, we see and diagnose only their downstream, daytime symptoms. There has been less research into sleep and A.D.H.D. outside of childhood. But a team from Massachusetts General Hospital found, in one of the only studies of its kind, that sleep dysfunction in adults with A.D.H.D. closely mimics the sleep dysfunction in children with A.D.H.D.

There is also some promising research being done on sleep in adults, relating to focus, memory and cognitive performance. A study published in February in the journal Nature Neuroscience found that the amount of delta sleep in seniors correlates with performance on memory tests. And a study published three years ago in Sleep found that while subjects who were deprived of sleep didn’t necessarily report feeling sleepier, their cognitive performance declined in proportion to their sleep deprivation and continued to worsen over five nights of sleep restriction.

As it happens, “moves about excessively during sleep” was once listed as a symptom of attention-deficit disorder in the Diagnostic and Statistical Manual of Mental Disorders. That version of the manual, published in 1980, was the first to name the disorder. When the term A.D.H.D., reflecting the addition of hyperactivity, appeared in 1987, the diagnostic criteria no longer included trouble sleeping. The authors said there was not enough evidence to support keeping it in.

But what if doctors, before diagnosing A.D.H.D. in their patients, did have to find evidence of a sleep disorder? Psychiatric researchers typically don’t have access to the equipment or expertise needed to evaluate sleep issues. It’s tricky to ask patients to keep sleep logs or to send them for expensive overnight sleep studies, which can involve complicated equipment like surface electrodes to measure brain and muscle activity; abdominal belts to record breathing; “pulse oximeters” to measure blood oxygen levels; even snore microphones. (And getting a sleep study approved by an insurance company is by no means guaranteed.) As it stands, A.D.H.D. can be diagnosed with only an office interview.

Sometimes my patients have resisted my referrals for sleep testing, since everything they have read (often through direct-to-consumer marketing by drug companies) identifies A.D.H.D. as the culprit. People don’t like to hear that they may have a different, stranger-sounding problem that can’t be fixed with a pill — though this often changes once patients see the results of their sleep studies.

Beyond my day job, I have a personal interest in A.D.H.D. and sleep disorders. Beginning in college and for nearly a decade, I struggled with profound cognitive lethargy and difficulty focusing, a daily nap habit and weekend sleep addiction. I got through my medical school exams only by the grace of good memorization skills and the fact that ephedra was still a legal supplement.

I was misdiagnosed with various maladies, including A.D.H.D. Then I underwent two sleep studies and, finally, was found to have an atypical form of narcolepsy. This was a shock to me, because I had never fallen asleep while eating or talking. But, it turned out, over 40 percent of my night was spent in REM sleep — or “dreaming sleep,” which normally occurs only intermittently throughout the night — while just 5 percent was spent in delta sleep, the rejuvenating kind. I was sleeping 8 to 10 hours a night, but I still had a profound delta sleep deficit.

It took some trial and error, but with the proper treatment, my cognitive problems came to an end. Today I eat well and respect my unique sleep needs instead of trying to suppress them. I also take two medications: a stimulant for narcolepsy and, at bedtime, an S.N.R.I. (or serotonin-norepinephrine reuptake inhibitor) antidepressant — an off-label treatment that curtails REM sleep and helps increase delta sleep. Now I wake up without an alarm, and my daytime focus is remarkably improved. My recovery has been amazing (though my wife would argue that weekend mornings are still tough — she picks up the slack with our two kids).

Attention-deficit problems are far from the only reasons to take our lack of quality sleep seriously. Laboratory animals die when they are deprived of delta sleep. Chronic delta sleep deficits in humans are implicated in many diseases, including depression, heart disease, hypertension, obesity, chronic pain, diabetes and cancer, not to mention thousands of fatigue-related car accidents each year.

Sleep disorders are so prevalent that every internist, pediatrician and psychiatrist should routinely screen for them. And we need far more research into this issue. Every year billions of dollars are poured into researching cancer, depression and heart disease, but how much money goes into sleep?

The National Institutes of Health will spend only $240 million on sleep research this year. One of the problems is that the research establishment exists as mini-fiefdoms — money given to one sector, like cardiology or psychiatry, rarely makes it into another, like sleep medicine, even if they are intimately connected.

But we can’t wait any longer to pay attention to the connection between delta sleep and A.D.H.D. If you’re not already convinced, consider the drug clonidine. It started life as a hypertension treatment, but has been approved by the Food and Drug Administration to treat A.D.H.D. Studies show that when it is taken only at bedtime, symptoms improve during the day. For psychiatrists, it is one of these “oh-we-don’t-know-how-it-works” drugs. But here is a little-known fact about clonidine: it can be a potent delta sleep enhancer.

Vatsal G. Thakkar is a clinical assistant professor of psychiatry at the N.Y.U. School of Medicine.

NEW YORK TIMES: APRIL 27, 2013

The Best Mattress For Stomach Sleepers

We’ve discussed how to find the best mattress for Back Sleepers: http://sovnsleep.blogspot.com/2013/05/the-best-mattress-for-back-sleepers.html

We’ve also discussed how to find the best mattress for Side Sleepers: http://sovnsleep.blogspot.com/2013/04/the-best-mattress-for-side-sleepers.html

If you go back and review the other two articles, you’ll find a recurring theme: the mattress that is best for you will be the one that holds your body in a neutral position.

To define “neutral position”: this is how you look when standing in a relaxed position. Generally, the hips and shoulders line up; the spinal column is gently curved.

If a mattress can keep you in your neutral position, it means that unnecessary muscular tension due to improper alignment and imbalance will be all but eliminated.

However, for true stomach sleepers, those who sleep flat on their bellies, the idea that you can find a mattress that will hold you in a neutral position is false.

You can certainly find a mattress that holds your body in a healthy way from the shoulders down. It’s the neck up that is, sadly, impossible.

When sleeping flat on the belly, (the prone position), the head must be turned drastically to one side in order to be able to breathe. This creates mispositioning of the cervical vertebrae and musculature issues due to such harsh flexion, resulting in neck pain.

Imagine holding your head in this position for extended periods of time during your daytime hours. It’s unthinkable, isn’t it? Still, many people do sleep in the prone position and find it difficult to re-train their bodies to a healthier sleeping position. So for those people, we offer the following suggestions.

The best mattress for the belly sleeper is the one that keeps the hips in the proper place. The mattress must be firm enough to create just enough lift under the hips so the gentle curvature of the lumbar spine remains intact and as it exists when the sleeper is standing up in a relaxed position.

How do you know if your hips are in the correct position? If the mattress is too soft, the hip region / pelvic girdle will enter too deeply into the mattress surface, which places excess curvature in the lumbar region—in effect, a swayback situation will occur.

If the mattress is too firm, there will be too much lift under the hips, resulting in a flattening of that all-important lumbar curvature.

Firm/Medium/Soft mattress: the one that works best for you is based on your weight. Try out models until one keeps the hips in the proper position and don’t worry about if it’s called a soft or firm. The importance of proper alignment (at least from the shoulders down for belly sleepers) supersedes the soft/firm question. And if you find one that keeps you in a correct position, that question answers itself.

Again, it’s so important to look carefully at the materials involved in the making of the mattress, and to inspect the warranty. What good does it do to find a mattress that fits your body perfectly if it’s going to wear out very quickly? And if the mattress gets worn out, your body is no longer in a neutral position, but is flexed in an unnatural, unhealthy way.

Most warranties contain a clause regarding “body impressions”—and most warranties will not go into effect until that body impression reaches a depth of at least 1.5 inches. When the body is lying in even a ½-inch-deep body impression, there’s no way for it to remain neutral, no matter what sleeping position you might be in. Please think carefully about longevity of the mattress as it relates to maintaining your healthy sleeping positions.

Also, please see the following link for information on what to look for (and look out for) in a mattress warranty: http://sovnsleep.blogspot.com/2012/12/mattress-warranties-what-you-need-to.html