The Importance of Sleep for Dancers; Treating Hand & Wrist Injuries

Episode 17.26 with Hosts Steve Kashul and Dr. Brian Cole. Broadcasting on ESPN Chicago 1000 WMVP-AM Radio, Saturdays from 8:30 to 9:00 AM/c.

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Segment One (01:25): Julie O’Connell PT, DPT, OCS, ATC, Performing Arts Medicine importance of sleep for dancersProgram Manager at Athletico-River North talks dancers vs other athletes regarding sleep; what happens during sleep for dancers and useful tips for quality sleep. While the days are getting shorter, rehearsals are getting longer and cutting into valuable time meant for counting sheep.

Julie specializes in the treatment of dancers and performing artists and has extensive experience working with organizations like The Joffrey Ballet, Hubbard Street Dance Chicago and Broadway in Chicago.

The CDC recommends 8-10 hours of sleep for teens 13-18 years old, and 7 or more hours per night for adults 18-60 years old. This can be difficult to achieve for dancers, whose rehearsals consist of specialized physical activity of high volume, frequency and intensity throughout the week. Dancers also don’t usually have an off-season, which can contribute to increased incidence of altered sleep-wake rhythms, illness and musculoskeletal injuries. More>>


Segment Two (13:11): Dr. John Fernandez from Midwest Orthopaedics at Rush describes microsurgery; recent innovations in hand and wrist surgery; re-plantation and transplantation of limbs; types of hand injuries experienced by athletes at all levels.

Dr. John FernandezDr. Fernandez has created and innovated some of the advanced surgeries currently popularized in the treatment of the hand, wrist, and elbow. His original research has led to techniques minimizing surgical trauma while maximizing outcomes. As an inventor, he holds patents in some of the very implants developed for these minimally invasive surgeries.

As director of microsurgery for Midwest Orthopaedics at Rush, he has performed hundreds of successful microsurgical procedures. These have included replantation of amputated arms, hands, and digits, as well as complex reconstructions for deformity and wounds.

He is a board certified member of the ABOS and holds the highest distinction in hand surgery with a certificate of added qualification in hand and microsurgery. He is a fellow of the American Academy of Orthopaedic Surgeons and a member of the American Association for Hand Surgery as well as the American Society for Surgery of the Hand.

The shorter your sleep, the shorter your life

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Matthew Walker has learned to dread the question “What do you do?” At parties, it signals the end of his evening; thereafter, his new acquaintance will inevitably cling to him like ivy. On an aeroplane, it usually means that while everyone else watches movies or reads a thriller, he will find himself running an hours-long salon for the benefit of passengers and crew alike. “I’ve begun to lie,” he says. “Seriously. I just tell people I’m a dolphin trainer. It’s better for everyone.”

Leading neuroscientist Matthew Walker on why sleep deprivation is increasing our risk of cancer, heart attack and Alzheimer’s – and what you can do about it.

Walker is a sleep scientist. To be specific, he is the director of the Center for Human Sleep Science at the University of California, Berkeley, a research institute whose goal – possibly unachievable – is to understand everything about sleep’s impact on us, from birth to death, in sickness and health. No wonder, then, that people long for his counsel. As the line between work and leisure grows ever more blurred, rare is the person who doesn’t worry about their sleep. But even as we contemplate the shadows beneath our eyes, most of us don’t know the half of it – and perhaps this is the real reason he has stopped telling strangers how he makes his living. When Walker talks about sleep he can’t, in all conscience, limit himself to whispering comforting nothings about camomile tea and warm baths. It’s his conviction that we are in the midst of a “catastrophic sleep-loss epidemic”, the consequences of which are far graver than any of us could imagine. This situation, he believes, is only likely to change if government gets involved.

Walker has spent the last four and a half years writing Why We Sleep, a complex but urgent book that examines the effects of this epidemic close up, the idea being that once people know of the powerful links between sleep loss and, among other things, Alzheimer’s disease, cancer, diabetes, obesity and poor mental health, they will try harder to get the recommended eight hours a night (sleep deprivation, amazing as this may sound to Donald Trump types, constitutes anything less than seven hours). But, in the end, the individual can achieve only so much. Walker wants major institutions and law-makers to take up his ideas, too. “No aspect of our biology is left unscathed by sleep deprivation,” he says. “It sinks down into every possible nook and cranny. And yet no one is doing anything about it. Things have to change: in the workplace and our communities, our homes and families. But when did you ever see an NHS poster urging sleep on people? When did a doctor prescribe, not sleeping pills, but sleep itself? It needs to be prioritised, even incentivised. Sleep loss costs the UK economy over £30bn a year in lost revenue, or 2% of GDP. I could double the NHS budget if only they would institute policies to mandate or powerfully encourage sleep.”

Why, exactly, are we so sleep-deprived? What has happened over the course of the last 75 years? In 1942, less than 8% of the population was trying to survive on six hours or less sleep a night; in 2017, almost one in two people is. The reasons are seemingly obvious. “First, we electrified the night,” Walker says. “Light is a profound degrader of our sleep. Second, there is the issue of work: not only the porous borders between when you start and finish, but longer commuter times, too. No one wants to give up time with their family or entertainment, so they give up sleep instead. And anxiety plays a part. We’re a lonelier, more depressed society. Alcohol and caffeine are more widely available. All these are the enemies of sleep.”

But Walker believes, too, that in the developed world sleep is strongly associated with weakness, even shame. “We have stigmatised sleep with the label of laziness. We want to seem busy, and one way we express that is by proclaiming how little sleep we’re getting. It’s a badge of honour. When I give lectures, people will wait behind until there is no one around and then tell me quietly: ‘I seem to be one of those people who need eight or nine hours’ sleep.’ It’s embarrassing to say it in public. They would rather wait 45 minutes for the confessional. They’re convinced that they’re abnormal, and why wouldn’t they be? We chastise people for sleeping what are, after all, only sufficient amounts. We think of them as slothful. No one would look at an infant baby asleep, and say ‘What a lazy baby!’ We know sleeping is non-negotiable for a baby. But that notion is quickly abandoned [as we grow up]. Humans are the only species that deliberately deprive themselves of sleep for no apparent reason.” In case you’re wondering, the number of people who can survive on five hours of sleep or less without any impairment, expressed as a percent of the population and rounded to a whole number, is zero.

The world of sleep science is still relatively small. But it is growing exponentially, thanks both to demand (the multifarious and growing pressures caused by the epidemic) and to new technology (such as electrical and magnetic brain stimulators), which enables researchers to have what Walker describes as “VIP access” to the sleeping brain. Walker, who is 44 and was born in Liverpool, has been in the field for more than 20 years, having published his first research paper at the age of just 21. “I would love to tell you that I was fascinated by conscious states from childhood,” he says. “But in truth, it was accidental.” He started out studying for a medical degree in Nottingham. But having discovered that doctoring wasn’t for him – he was more enthralled by questions than by answers – he switched to neuroscience, and after graduation, began a PhD in neurophysiology supported by the Medical Research Council. It was while working on this that he stumbled into the realm of sleep.

“I was looking at the brainwave patterns of people with different forms of dementia, but I was failing miserably at finding any difference between them,” he recalls now. One night, however, he read a scientific paper that changed everything. It described which parts of the brain were being attacked by these different types of dementia: “Some were attacking parts of the brain that had to do with controlled sleep, while other types left those sleep centres unaffected. I realised my mistake. I had been measuring the brainwave activity of my patients while they were awake, when I should have been doing so while they were asleep.” Over the next six months, Walker taught himself how to set up a sleep laboratory and, sure enough, the recordings he made in it subsequently spoke loudly of a clear difference between patients. Sleep, it seemed, could be a new early diagnostic litmus test for different subtypes of dementia.

After this, sleep became his obsession. “Only then did I ask: what is this thing called sleep, and what does it do? I was always curious, annoyingly so, but when I started to read about sleep, I would look up and hours would have gone by. No one could answer the simple question: why do we sleep? That seemed to me to be the greatest scientific mystery. I was going to attack it, and I was going to do that in two years. But I was naive. I didn’t realise that some of the greatest scientific minds had been trying to do the same thing for their entire careers. That was two decades ago, and I’m still cracking away.” After gaining his doctorate, he moved to the US. Formerly a professor of psychiatry at Harvard Medical School, he is now professor of neuroscience and psychology at the University of California.

Does his obsession extend to the bedroom? Does he take his own advice when it comes to sleep? “Yes. I give myself a non-negotiable eight-hour sleep opportunity every night, and I keep very regular hours: if there is one thing I tell people, it’s to go to bed and to wake up at the same time every day, no matter what. I take my sleep incredibly seriously because I have seen the evidence. Once you know that after just one night of only four or five hours’ sleep, your natural killer cells – the ones that attack the cancer cells that appear in your body every day – drop by 70%, or that a lack of sleep is linked to cancer of the bowel, prostate and breast, or even just that the World Health Organisation has classed any form of night-time shift work as a probable carcinogen, how could you do anything else?”

There is, however, a sting in the tale. Should his eyelids fail to close, Walker admits that he can be a touch “Woody Allen-neurotic”. When, for instance, he came to London over the summer, he found himself jet-lagged and wide awake in his hotel room at two o’clock in the morning. His problem then, as always in these situations, was that he knew too much. His brain began to race. “I thought: my orexin isn’t being turned off, the sensory gate of my thalamus is wedged open, my dorsolateral prefrontal cortex won’t shut down, and my melatonin surge won’t happen for another seven hours.” What did he do? In the end, it seems, even world experts in sleep act just like the rest of us when struck by the curse of insomnia. He turned on a light and read for a while.

Will Why We Sleep have the impact its author hopes? I’m not sure: the science bits, it must be said, require some concentration. But what I can tell you is that it had a powerful effect on me. After reading it, I was absolutely determined to go to bed earlier – a regime to which I am sticking determinedly. In a way, I was prepared for this. I first encountered Walker some months ago, when he spoke at an event at Somerset House in London, and he struck me then as both passionate and convincing (our later interview takes place via Skype from the basement of his “sleep centre”, a spot which, with its bedrooms off a long corridor, apparently resembles the ward of a private hospital). But in another way, it was unexpected. I am mostly immune to health advice. Inside my head, there is always a voice that says “just enjoy life while it lasts”.

The evidence Walker presents, however, is enough to send anyone early to bed. It’s no kind of choice at all. Without sleep, there is low energy and disease. With sleep, there is vitality and health. More than 20 large scale epidemiological studies all report the same clear relationship: the shorter your sleep, the shorter your life. To take just one example, adults aged 45 years or older who sleep less than six hours a night are 200% more likely to have a heart attack or stroke in their lifetime, as compared with those sleeping seven or eight hours a night (part of the reason for this has to do with blood pressure: even just one night of modest sleep reduction will speed the rate of a person’s heart, hour upon hour, and significantly increase their blood pressure).

A lack of sleep also appears to hijack the body’s effective control of blood sugar, the cells of the sleep-deprived appearing, in experiments, to become less responsive to insulin, and thus to cause a prediabetic state of hyperglycaemia. When your sleep becomes short, moreover, you are susceptible to weight gain. Among the reasons for this are the fact that inadequate sleep decreases levels of the satiety-signalling hormone, leptin, and increases levels of the hunger-signalling hormone, ghrelin. “I’m not going to say that the obesity crisis is caused by the sleep-loss epidemic alone,” says Walker. “It’s not. However, processed food and sedentary lifestyles do not adequately explain its rise. Something is missing. It’s now clear that sleep is that third ingredient.” Tiredness, of course, also affects motivation.

Sleep has a powerful effect on the immune system, which is why, when we have flu, our first instinct is to go to bed: our body is trying to sleep itself well. Reduce sleep even for a single night, and your resilience is drastically reduced. If you are tired, you are more likely to catch a cold. The well-rested also respond better to the flu vaccine. As Walker has already said, more gravely, studies show that short sleep can affect our cancer-fighting immune cells. A number of epidemiological studies have reported that night-time shift work and the disruption to circadian sleep and rhythms that it causes increase the odds of developing cancers including breast, prostate, endometrium and colon.

Getting too little sleep across the adult lifespan will significantly raise your risk of developing Alzheimer’s disease. The reasons for this are difficult to summarise, but in essence it has to do with the amyloid deposits (a toxin protein) that accumulate in the brains of those suffering from the disease, killing the surrounding cells. During deep sleep, such deposits are effectively cleaned from the brain. What occurs in an Alzheimer’s patient is a kind of vicious circle. Without sufficient sleep, these plaques build up, especially in the brain’s deep-sleep-generating regions, attacking and degrading them. The loss of deep sleep caused by this assault therefore lessens our ability to remove them from the brain at night. More amyloid, less deep sleep; less deep sleep, more amyloid, and so on. (In his book, Walker notes “unscientifically” that he has always found it curious that Margaret Thatcher and Ronald Reagan, both of whom were vocal about how little sleep they needed, both went on to develop the disease; it is, moreover, a myth that older adults need less sleep.) Away from dementia, sleep aids our ability to make new memories, and restores our capacity for learning.

And then there is sleep’s effect on mental health. When your mother told you that everything would look better in the morning, she was wise. Walker’s book includes a long section on dreams (which, says Walker, contrary to Dr Freud, cannot be analysed). Here he details the various ways in which the dream state connects to creativity. He also suggests that dreaming is a soothing balm. If we sleep to remember (see above), then we also sleep to forget. Deep sleep – the part when we begin to dream – is a therapeutic state during which we cast off the emotional charge of our experiences, making them easier to bear. Sleep, or a lack of it, also affects our mood more generally. Brain scans carried out by Walker revealed a 60% amplification in the reactivity of the amygdala – a key spot for triggering anger and rage – in those who were sleep-deprived. In children, sleeplessness has been linked to aggression and bullying; in adolescents, to suicidal thoughts. Insufficient sleep is also associated with relapse in addiction disorders. A prevailing view in psychiatry is that mental disorders cause sleep disruption. But Walker believes it is, in fact, a two-way street. Regulated sleep can improve the health of, for instance, those with bipolar disorder.

I’ve mentioned deep sleep in this (too brief) summary several times. What is it, exactly? We sleep in 90-minute cycles, and it’s only towards the end of each one of these that we go into deep sleep. Each cycle comprises two kinds of sleep. First, there is NREM sleep (non-rapid eye movement sleep); this is then followed by REM (rapid eye movement) sleep. When Walker talks about these cycles, which still have their mysteries, his voice changes. He sounds bewitched, almost dazed.

“During NREM sleep, your brain goes into this incredible synchronised pattern of rhythmic chanting,” he says. “There’s a remarkable unity across the surface of the brain, like a deep, slow mantra. Researchers were once fooled that this state was similar to a coma. But nothing could be further from the truth. Vast amounts of memory processing is going on. To produce these brainwaves, hundreds of thousands of cells all sing together, and then go silent, and on and on. Meanwhile, your body settles into this lovely low state of energy, the best blood-pressure medicine you could ever hope for. REM sleep, on the other hand, is sometimes known as paradoxical sleep, because the brain patterns are identical to when you’re awake. It’s an incredibly active brain state. Your heart and nervous system go through spurts of activity: we’re still not exactly sure why.”

Does the 90-minute cycle mean that so-called power naps are worthless? “They can take the edge off basic sleepiness. But you need 90 minutes to get to deep sleep, and one cycle isn’t enough to do all the work. You need four or five cycles to get all the benefit.” Is it possible to have too much sleep? This is unclear. “There is no good evidence at the moment. But I do think 14 hours is too much. Too much water can kill you, and too much food, and I think ultimately the same will prove to be true for sleep.” How is it possible to tell if a person is sleep-deprived? Walker thinks we should trust our instincts. Those who would sleep on if their alarm clock was turned off are simply not getting enough. Ditto those who need caffeine in the afternoon to stay awake. “I see it all the time,” he says. “I get on a flight at 10am when people should be at peak alert, and I look around, and half of the plane has immediately fallen asleep.”

So what can the individual do? First, they should avoid pulling “all-nighters”, at their desks or on the dancefloor. After being awake for 19 hours, you’re as cognitively impaired as someone who is drunk. Second, they should start thinking about sleep as a kind of work, like going to the gym (with the key difference that it is both free and, if you’re me, enjoyable). “People use alarms to wake up,” Walker says. “So why don’t we have a bedtime alarm to tell us we’ve got half an hour, that we should start cycling down?” We should start thinking of midnight more in terms of its original meaning: as the middle of the night. Schools should consider later starts for students; such delays correlate with improved IQs. Companies should think about rewarding sleep. Productivity will rise, and motivation, creativity and even levels of honesty will be improved. Sleep can be measured using tracking devices, and some far-sighted companies in the US already give employees time off if they clock enough of it. Sleeping pills, by the way, are to be avoided. Among other things, they can have a deleterious effect on memory.

Those who are focused on so-called “clean” sleep are determined to outlaw mobiles and computers from the bedroom – and quite right, too, given the effect of LED-emitting devices on melatonin, the sleep-inducing hormone. Ultimately, though, Walker believes that technology will be sleep’s saviour. “There is going to be a revolution in the quantified self in industrial nations,” he says. “We will know everything about our bodies from one day to the next in high fidelity. That will be a seismic shift, and we will then start to develop methods by which we can amplify different components of human sleep, and do that from the bedside. Sleep will come to be seen as a preventive medicine.”

What questions does Walker still most want to answer? For a while, he is quiet. “It’s so difficult,” he says, with a sigh. “There are so many. I would still like to know where we go, psychologically and physiologically, when we dream. Dreaming is the second state of human consciousness, and we have only scratched the surface so far. But I would also like to find out when sleep emerged. I like to posit a ridiculous theory, which is: perhaps sleep did not evolve. Perhaps it was the thing from which wakefulness emerged.” He laughs. “If I could have some kind of medical Tardis and go back in time to look at that, well, I would sleep better at night.”

Sleep in numbers

■ Two-thirds of adults in developed nations fail to obtain the nightly eight hours of sleep recommended by the World Health Organisation.

■ An adult sleeping only 6.75 hours a night would be predicted to live only to their early 60s without medical intervention.

■ A 2013 study reported that men who slept too little had a sperm count 29% lower than those who regularly get a full and restful night’s sleep.

■ If you drive a car when you have had less than five hours’ sleep, you are 4.3 times more likely to be involved in a crash. If you drive having had four hours, you are 11.5 times more likely to be involved in an accident.

■ A hot bath aids sleep not because it makes you warm, but because your dilated blood vessels radiate inner heat, and your core body temperature drops. To successfully initiate sleep, your core temperature needs to drop about 1C.

■ The time taken to reach physical exhaustion by athletes who obtain anything less than eight hours of sleep, and especially less than six hours, drops by 10-30%.

■ There are now more than 100 diagnosed sleep disorders, of which insomnia is the most common.

■ Morning types, who prefer to awake at or around dawn, make up about 40% of the population. Evening types, who prefer to go to bed late and wake up late, account for about 30%. The remaining 30% lie somewhere in between.

Tips to Help Student Athletes Reach Peak Performance

Tips to Help Student Athletes Reach Peak PerformanceBy Athletico Physical Therapy

The Fall sport season is right around the corner! With the start of a new school year and a new sports team, the beginning of the season can be tough. Regardless of what sport is being played, there are many factors that can help student athletes have a great tryout and season, including the four tips outlined below.

ShoesProper equipment and gear at the start of the season can be a great way to prevent injuries and help athletes get an extra performance boost! Shoes are known for enduring lots of wear and tear. Worn out shoes can potentially cause foot pain and lead to overuse injuries that inhibit athletic ability. Investing in new shoes can provide athletes with more comfort, allowing them to reach peak performance. However, it is important to break in new shoes before playing in them. Doing so can help to prevent blisters and other discomfort that could occur.

Sleep: Getting a good night sleep helps athletes feel rested and ready for early morning trainings! Sleeping is essential for helping the body recover. In fact, the National Sleep Foundation notes that when sleep is cut short, the body doesn’t have enough time to complete all of the phases needed for things like muscle repair or memory consolidation. This is why it is important for athletes to gain enough shuteye before tryouts, practice and games!

Nutrition: As the season begins, the importance of nutrition should be remembered. Eating consistent healthy meals helps fuel the body and provides energy that is needed to perform. Athletes should focus on consuming enough carbohydrates from the proper sources. Good food sources include pasta, bread, cereal, fruit and vegetables. Carbohydrates are a significant contributor to an athlete’s energy, so it is important to eat the right amount. Protein can also influence performance and help the body maintain its strength. A few good sources of protein include meats, fish, beans, eggs and milk. By having a balanced diet, athletes will have the energy needed to succeed.

HydrationHydration is another aspect of nutrition that can affect performance. It is important to stay ahead of dehydration by drinking water consistently throughout the day. Athletes should always have a water bottle handy, including at practices so that enough fluids are consumed during physical activity. Since the recommendations for staying hydrated vary from person to person, consider learning more about sweat rate by reading Athletico’s “Hydration for Performance and Health.

Reaching Peak Performance

Student athletes have a lot to focus on during the school year. These tips can help athletes stay healthy and reach their peak performance for tryouts and games. Should any aches or pains during training occur, make sure to schedule a complimentary injury screen at your nearest Athletico so you can get back in the game as soon as possible.

Schedule a Complimentary Injury Screen

The Sleep Cure: The Fountain of Youth May Be Closer Than You Ever Thought

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Mark Zielinski knew he was onto something when his mice stopped sleeping. Normally, the animals woke and slept on a 12-hour cycle. When the lights were on in the lab, the mice were active. When it went dark on a timer, down they went. But Zielinski, who teaches psychiatry at Harvard Medical School, had recently tweaked their schedule to keep the mice up past their bedtime.

Zielinski and his colleagues would rustle the bedding in the mice’s cages to keep them from dozing off when they started to display the telltale signs of sleepiness–drooping lids, sluggish walk, EEG readings showing their brain activity was waning. But Zielinski noticed that when the mice were left alone to slumber at will after the disruption, they didn’t, or perhaps couldn’t, fall asleep.

That the sleep-deprived rodents slept less than they normally would didn’t really surprise Zielinski. The mice had a genetic mutation that he suspected was linked to sleep problems. More striking were the electrical brain readings showing that even when they did sleep, they weren’t getting the deep, restorative kind of rest that doctors say matters most–not just to rodents but also to humans.

In the right conditions, researchers believe, the brain produces a signal that essentially tells the body’s major systems–the heart, the lungs, the digestive system, the nervous system, even the muscles–that it’s time to call it quits for the day. Zielinski’s research has found that, just as with the mice with the mutation, it’s likely that in some people with chronic sleep problems, that critical signal isn’t firing.

Understanding what’s behind some forms of insomnia, an aim of Zielinski’s research, is a major step in learning how to fix it. That’s a big deal in sleep research, because evidence linking quality rest to good health and longevity has never been more convincing.


Scientists are learning that shortchanging sleep can compromise nearly every major body system, from the brain to the heart to the immune system, making our inability–or unwillingness–to sleep enough one of the unhealthiest things we can do.


Studies of people whose sleep sessions are irregular or short show they are at higher risk of developing diseases that can lead to early death, including heart disease, diabetes, high blood pressure and obesity. Poor sleep may have detrimental effects on the brain as well, increasing the risk of dementia, including Alzheimer’s disease, as well as mood disorders like depression, post traumatic stress disorder (PTSD) and anxiety. And like smoking, a terrible diet and not exercising enough, poor sleep is now linked to an overall increased risk of premature death.

“I used to suggest that sleep is the third pillar of good health, along with diet and exercise,” says Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley. “But I don’t agree with that anymore. Sleep is the single most effective thing you can do to reset your brain and body for health.”

Despite the mounting evidence of its benefits, Americans are sleeping about two hours less each night than they did a century ago. Blame the technology-fueled 24/7 workplace, social media or the relentless news cycle, but about one-third of U.S. adults sleep less than the recommended seven hours daily, and 40% report feeling drowsy during the day, according to data from the Centers for Disease Control and Prevention. The problem begins early: only 15% to 30% of U.S. teens get the 8½ hours a night recommended for adolescents.

While life expectancy has been inching upward over the past century thanks to advances in medicine and technology, those gains could start to sag under the weight of our collective sleeplessness. Many people still dismiss sleep as something they can occasionally (or even regularly) skimp on, but the biological facts are clear: it is neither safe nor wise to take sleep lightly.


“To me, sleep is like the canary in the coal mine,” says David Schnyer, a professor of psychology and neuroscience at the University of Texas, Austin. “Changes in sleep can create system wide changes in the organism, and all of the stages of sleep affect the entire body and brain.”


That’s why sleep deprivation is so strongly linked to disease and premature death. One recent study even showed that sleep deprivation in mice can cause death faster than starvation can. And yet doctors–those who talk to their patients about sleep in the first place, anyway–report that many people still aren’t convinced that their nightly rest is a critical piece of the long-life puzzle. Health obsessives who would never touch a cigarette and pride themselves on avoiding junk food may also boast about how much they get done, and how little they sleep at night.

“Because we’re asleep, we don’t see the benefits of it,” says Robert Stickgold, a well-known sleep researcher and an associate professor of psychiatry at Harvard Medical School. “That’s the disaster and tragedy of our current world.”

It’s been that way for a long time. Benjamin Franklin famously quipped that “there will be sleeping enough in the grave,” and today, sleep is still misperceived as one of the most duty-driven and unproductive parts of the day–the habit that gets in the way of life as opposed to the one most likely to extend it.

Perhaps that’s because until very recently, scientists couldn’t even agree on the evolutionary reason why animals need to sleep in the first place. But now they know that what happens during sleep, particularly in the brain, is critical to human well-being–not to mention a long life. That’s why they also know that the cost of ignoring the latest science on sleep can be dear.

Spending a good third of the day oblivious to the world around you and, by extension, incapable of protecting yourself doesn’t seem like a smart way for a species to stay alive. And yet every animal does it, leading scientists to accept that sleep must be nonnegotiable for some reason–and that we must need a certain amount of it to survive.

Following a rigorous, milestone study in 2002 of more than 1 million healthy men and women by the American Cancer Society, experts suggested that the magic amount of sleep for longevity was seven hours a night. People who slept that amount were most likely to still be alive at the end of the study’s six years, compared with people who got either six hours or less, or eight hours or more, of sleep each night. To this day, that’s typically the amount that doctors and public-health groups recommend for the average adult, though older people can probably get away with a little less sleep than that, and younger people need more.

Another even longer study, which followed more than 21,000 twins in Finland, found that people who were regularly sleeping less than seven hours daily were 21% to 26% more likely to die of any cause during the study’s 22-year period than those who slept more than eight hours.

So clearly sleep has some real biological benefit. Could it just be that the brain and body need downtime to recuperate after the activity of the day? That was the most popular explanation for decades, until an inquisitive neuroscientist at the University of Rochester decided to look for the answer inside the brain itself. When she did, Dr. Maiken Nedergaard uncovered what many scientists now agree is sleep’s primary evolutionary function: to clean out the brain, quite literally, of accumulating debris.

In 2014, Nedergaard first revealed that while the body appears to rest during sleep, a whole lot is happening inside the brain. Neurons pulse with electrical signals that wash over the brain in a rhythmic flow. The brain runs checks on itself to ensure that the balance of hormones, enzymes and proteins isn’t too far off-kilter. All the while, brain cells contract, opening up the spaces between them so that fluid can wash out the toxic detritus that can cause all kinds of problems if it builds up.

“It’s like a dishwasher that keeps flushing through to wash the dirt away,” Nedergaard says.

Without that nightly wash cycle, dangerous toxins can damage healthy cells and interfere with their ability to communicate with one another. In the short term, that can impede memory formation and the ability to coherently compose our thoughts and regulate our emotions. Over time, the consequences can be more dire. Lack of sleep can lead to faster aging of brain cells, contributing to diseases like Alzheimer’s, which is now the cause of death for 1 in 3 seniors.

Nedergaard’s research, which was done in mice, prompted a crucial rethinking of not only the benefits of sleep but also its biological function. It turns out the brain and body are extremely active when we sleep–we’re just not aware of most of what occurs while we do it.

“Sleep is not just a passive state but a fairly active state on the molecular level,” says Dr. Allan Pack, director of the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania. “During the day, the brain is using energy resources to fire neurons. At night, a switch turns on so the sleeping brain can take advantage of the metabolic downtime to do some cleaning up.”


The idea that sleep is a time of important biological activity, rather than a period when the body checks out, is transforming how doctors think about another important factor in longevity: mental health.


Scientists have long known that sleep is important for memory. But it turns out that during sleep, especially the cycles of deep dream sleep, the brain doesn’t just revisit the events of a day in a more organized way. It also works on processing the emotions attached to these recollections. When a memory is filed away during sleep, it’s also stripped of some of the powerful feelings–like fear, grief, anger or joy–that might have clouded the experiences in the heat of the moment.

It wouldn’t be healthy, or efficient, to remember every event or experience in its full factual and emotional context. But separating the emotional aspects of a memory–the anger over an argument with your spouse, the frustration at the guy who cut you off in traffic, the dejection you felt after getting a curt email reply from your boss–from its objective parts allows you to recall the experience without reliving it. “We sleep to remember and we sleep to forget,” says Walker, the UC Berkeley sleep scientist, of this coping mechanism. “I call it overnight therapy.”

This type of processing takes time. It likely happens only during deep, quality sleep, and only over consistent nights of such sleep. That may explain why people who cut their sleep short or experience interrupted sleep may not fully disentangle the emotional baggage from their memories.

In those cases the memory, in its emotionally taxing entirety, continues to resurface every time the brain tries to sleep, in a vain effort to be properly processed. The brain tries to store the memory in a neutral way, but without deep sleep, there just isn’t enough time for that triage.

Walker believes these aborted efforts may drive conditions like PTSD, which is well understood to be common among combat veterans but which may be more common among the general population than therapists and researchers previously thought.

“The more nights you sleep, the more soothing the influence of sleep on that memory,” he says. “Sleep continues to work on those emotional memories and flatten them out after about a week. Now there’s great evidence that PTSD is a disorder in which that process fails.”

Walker saw this effect firsthand when he showed a group of people a frightening video. He kept some of the people awake after the viewing and allowed the rest to sleep normally. Those who were not allowed to sleep properly were more likely to remember the negative aspects of the video than those who got enough sleep.

There’s also strong support for the idea that insufficient sleep may be a trigger for, and not just a symptom of, a number of mental illnesses, including depression, bipolar disorder and even schizophrenia. Depriving people with bipolar disorder of sleep, for example, can launch a manic episode, while some people with depression report worsening symptoms when they aren’t sleeping well.

Fully understanding the role sleep plays in mental illness is a rich area of future research. Already many doctors think consistent, high-quality sleep can have a direct bearing on the health of those with mental illness. “Anyone who suffers from moderate or significant mental-health concerns needs to be aware that sleep may be one of the most important things they can do,” says Walker.

Stress, scientists also know, is one of the more potent accelerators of aging, and a body that’s not sleeping enough looks similar to one that’s stressed out–it’s highly reactive to perceived threats, even when those threats don’t pose any real risk. Biologically speaking, there’s virtually no difference in the way a body reacts to a startling noise in the middle of the night, a rabid raccoon or a stressful work deadline: in all cases, fight-or-flight mode is triggered, blood pressure spikes, breathing gets shallow, and the heart starts to race. That’s what happens to a body on no sleep too.

Those stress reactions can be useful, of course: they help you respond more readily to an actual physical threat. But that’s not usually what’s going on. And staying in an alert mode can trigger a number of unhealthy conditions, the most damaging of which is inflammation.

Inflammation is the body’s natural defense system against injury or invading microbes like bacteria and viruses. It’s why your toe turns red and throbs when you stub it or when it’s infected: white blood cells rush to the area in order to protect it for the short time it’s needed to help you get better. But inflammation can also become chronic, and that’s when the real trouble starts.


Chronic inflammation, doctors now know, is a leading driver of many diseases, including some cancers, cognitive decline, heart disease, Type 2 diabetes–even chronic pain. And one of the main drivers of chronic inflammation is, of course, not sleeping enough.


Getting a decent night’s sleep, then, is good advice for all of us. Americans spent an estimated $41 billion on sleeping pills and other sleep aids in 2015; no matter how much we may boast about our stamina, we know intuitively that we need sleep, even if we don’t always know why.

But scientists do. That’s why experts are insisting, with increasing frequency and noise, that sleep be a priority–as important or more than what you eat and how much you exercise. We wouldn’t dream of skipping meals on a regular basis, so why skimp on sleep?

There’s still much about sleep that mystifies scientists–particularly about what goes wrong for so many of us, night after night. But as they chip away at the underlying causes of sleeplessness, they get ever closer to a cure. Harvard’s Zielinski, for one, is hopeful that they will eventually find a way to help more people sleep better every night.

When he gave his sleepless mice a drug to fix the mutation that was interfering with their sleep in the first place, they began to slumber anew.

By Alice Park for Time Health