The Story of Stories

The transcript below may be for an earlier version of this episode. Our transcripts are provided by various partners and may contain errors or deviate slightly from the audio.

Shankar Vedantam: This is Hidden Brain. I'm Shankar Vedantam. Across the world, many countries are experiencing a sleep crisis. In the United States, 50 to 70 million Americans have sleep disorders. In India, almost 60% of adults get less than 6 hours of sleep every night. Sleep deprivation can make us groggy and irritable. Chronic sleep deprivation can rewire our brains and wear down our bodies. It can change how we parent, how we work with others, even what we value.

This week on Hidden Brain and in a companion episode on Hidden Brain Plus, what happens when a basic human need is jeopardized by an always on culture, and techniques to help you get a restful night of sleep.

Shankar Vedantam: We all know that sleep matters, and we all know what happens when we miss a night of sleep. At the University of Washington, sleep researcher Chris Barnes has studied what happens when the need for rest and the need to work collide. He says the consequences of not getting enough sleep extend far beyond what most of us imagine.

Chris Barnes, welcome to Hidden Brain.

Chris Barnes: I'm happy to be here, Shankar.

Shankar Vedantam: Chris, you've studied the effects of sleep deprivation for many years.

Shankar Vedantam: One story in particular has stayed with you. It involves a man named William Rockefeller. Can you tell me his story?

Chris Barnes: So William Rockefeller was a train engineer in New York, and he had a route that started early in the morning from Poughkeepsie, headed to New York City.

Shankar Vedantam: So the reason William Rockefeller ended up in the news one day was because of something that happened as he was making this train journey. Tell me what happened, Chris.

Chris Barnes: So as he was operating this train early in the morning, he sped through a section of the track in which he could go 70 miles an hour, ended up going a little faster than that, closer to 80 miles an hour, and continued that speed as it came to a curve.

This curve had a speed limit of 35, but he did not slow his train down to that speed fast enough to avoid a disaster.



Shankar Vedantam: I understand that he hit the break, but just not in time?

Chris Barnes: Yes, it was too little, too late, and the train derailed, four people were killed and 60 were injured.

Shankar Vedantam: So when investigators looked into the source of the problem, tell me what they found.

Chris Barnes: Well, initially, the train conductor's statement was that he felt like he entered a state of being sort of dazed or mesmerized while he was operating the train. Later, it came out that likely he actually fell asleep while he was operating the train, and then woke up too late to slow the train down to an appropriate speed for that curve. So, essentially, he fell asleep and that led him to crash the train.

Shankar Vedantam: So, as the train came roaring up to this curved section of the track, presumably he woke up and he hit the brakes, but that was too little too late.

Chris Barnes: Exactly.

Shankar Vedantam: I understand this train operator also suffered from sleep apnea, Chris?

Chris Barnes: Yes, he had a history of sleep apnea, which is a sleep disorder that is very disruptive to people's sleep.

Essentially, when you have sleep apnea, your airway closes off and you stop breathing, and then usually you choke yourself awake, and this might happen as many as hundreds of times per hour.

So it is quite disruptive to people's sleep. And even if you think you're getting a lot of sleep while you have sleep apnea, the quality of that sleep is poor, and the amount of sleep is usually much less than people think.

You can imagine how frustrating this would be to experience sleep apnea, where there are so many of these events throughout the night that you don't even remember all of the awakenings, because they were just too numerous, and you're kind of groggy when they happen.

Shankar Vedantam: I understand the National Transportation Safety Board investigated this crash that took place, Chris. Did they identify a lack of sleep or sleep on the part of the operator as the source of the problem?



Chris Barnes: Well, they mentioned several causal factors, one of which would be his recent change from a day schedule to a morning schedule. So there's some potential for circadian disruption in addition to his sleep apnea sort of stacking together, as setting the stage for a higher likelihood than would otherwise be the case for him falling asleep on the job.

And perhaps it's not surprising that that's exactly what happened to him.

Shankar Vedantam: So this incident took place in December 2013, and a similar story took place in 21 in the United Kingdom. But this time the problem was not with a train operator, but with a motorist named Gary Hart. Tell me that story, Chris.

Chris Barnes: So Mr.Hart was operating his vehicle, which was pulling a trailer that had another car on the trailer. And he had driven through much of the night. This was an early morning event, and he fell asleep while driving. And his vehicle veered off the road down an embankment and onto some train tracks. He tried to reverse off the train tracks, but was stuck and could not get his vehicle off. So he exited the vehicle and called the emergency services. And unfortunately, that's when disaster struck.

Shankar Vedantam: What happened?

Chris Barnes: So a train was already on those same tracks. It is his direction. And you can actually hear on his recorded emergency services call, the train actually striking his vehicle.

And that train was derailed and deflected in the direction of another train coming the opposite direction, which produced a head-on collision between the two trains. It produced several fatalities and many injuries as well.

Shankar Vedantam: I understand that 10 people were killed and 82 were injured, making it the worst rail disaster in the United Kingdom in the 21st century. You know, perhaps there were many factors you could argue, but one of the principal factors was that, you know, Barry Hart drove off the road in the first place because he was asleep.

Chris Barnes: Exactly.

Fell asleep at the wheel and woke up as his vehicle was going down that embankment onto the train track, but that was obviously too late to prevent the disaster from occurring.

Shankar Vedantam: So typically, when incidents like this take place, Chris, our tendency is to blame the people involved, to blame the motorist who fell asleep, to blame the train operator who was drowsy.



Shankar Vedantam: At some level, of course, these individuals have to take responsibility for what happened, but you say that this ignores a more serious part of the problem, Chris?

Chris Barnes: Yes. So we usually prefer simple, easy answers. We prefer to look for proximal factors that are simple to diagnose, and then we can dismiss the whole thing, like operator error. Human error is sort of a catch-all that we often use when we have disasters like these happen, but we don't often ask the question, okay, why did that human error occur? Why did this person fall asleep while they were doing something that is dangerous to do while they're asleep? So we need to zoom out and look at more systemic factors surrounding that decision without necessarily totally absolving the person who fell asleep on the job.

They bear some responsibility as well, but it's never that simple. This is always something that occurs in the context of many other factors, often which operate in concert in the same direction, pushing people towards sleep deprivation.

Shankar Vedantam: So I mean, it's not like William Rockefeller and Gary Hart had these long histories of accidents and problems. These were one-off incidents, obviously terrible incidents, but they were one-off incidents, which does raise the question, what else was going on besides what was happening in these individual people's lives?

Chris Barnes: Exactly. On other days of driving, they were perfectly safe. They did not fall asleep at the wheel. And there were other people that day who didn't fall asleep. But those other people, perhaps in the right context, might make the same mistake.

Shankar Vedantam: So Chris, you became a father to twins in 2019. You already had a three-year-old at home at the time. I'm imagining this was a time in your life when you weren't getting much sleep?

Chris Barnes: Yes, it was overwhelming. The way I like to think of it is, imagine all of the challenges and difficulties of a newborn and how disruptive that is to your sleep, and then add a second newborn to that same equation. So if somebody hands you a second baby and says, here, deal with this as well. So all of the feeding and changing cycles are longer, and nobody sleeps well in the situation. The babies don't sleep well, the parents don't sleep well. I certainly didn't sleep very well.

Shankar Vedantam: And you also had another little one at home at the time?

Chris Barnes: Yes, I had a three-year-old who also required attention and love and caring for.

Chris Barnes: The cumulative duties at home between the twins and my three-year-old were quite high. So I actually have very little memory of that time period, other than sluggishly washing bottles and changing diapers and just trying to survive.

Shankar Vedantam: Yeah. So one night you get an urgent call from your mom. Describe for me what she said and what happened next, Chris.

Chris Barnes: So for context, my parents, especially my father, had been in poor health for a few decades. And so some corner of my mind was always concerned that the next call I get from my mom could be that call that perhaps my father was dying. So in this particular occasion, my mother called me at three in the morning.

And that timing is already indicative that something is not going well. So she called me quite distressed saying that she had found my father lying on the floor, unresponsive, passed out. It wasn't clear how long he had been there, but they were on their way to the hospital. And so my first thought was, okay, this is the call I've been expecting. I need to go see them right away.

This might be my last chance to see my father while he's still alive.

Shankar Vedantam: So I'm imagining that you probably hopped in the car and raced to the hospital, Chris.

Chris Barnes: Exactly. So the hospital was about an hour from my home.

And so I immediately got into the car and drove down there despite it being roughly three in the morning, in a time period in which I was already not sleeping much anyway.

Shankar Vedantam: So tell me what happened once you got to the hospital. How was your dad?

Chris Barnes: I got to the hospital and spent a few hours talking with my parents. My dad turns out he was okay. It was just a scary event that wasn't so dangerous to his health after all. So he was okay. I had that chance to spend some time with him, but I still had two babies at home and a three-year-old. And my wife at the time was the only one looking after all three of them.

Shankar Vedantam: So I'm imagining you must have jumped back in the car and now try to race home.

Chris Barnes: Exactly right. So I felt both physically and emotionally exhausted. The physical exhaustion was due to an accumulation of sleep deprivation over the preceding weeks and more. And plus the wakening and the rapid drive down to the hospital at 3 a.m. Plus the emotional exhaustion of thinking that perhaps this is when my father is about to die. So those two stacked on top of each other just left me feeling completely drained. My eyes were bleary. I did not crash on the way home, but I did have a moment where I fell asleep while driving on the freeway for probably a few seconds. I can only guess, but my estimation, it was somewhere around three to five seconds, going straight on I-5 at highway speeds.

Shankar Vedantam: Now, three to five seconds going at 60, 70 miles an hour, you cover a lot of distance in three to five seconds, Chris.

Chris Barnes: Yes. As soon as I woke up, I had this jolt of fear and guilt and anger at myself. Knowing that I had just done a really stupid thing, that there is no way I should have made that decision, that I just put not only my life at risk, but all the drivers around me. Sometimes I still think about that moment. And I think about the fact that in the multiverse, some swath of that multiverse, I am the villain in some family story.

Because as I fell asleep, I crashed into another vehicle and caused some tragedies.

Shankar Vedantam: So, we've been talking about individual stories here, and people can say, well, these are anecdotes, but there's data as well. One comes from places like Taiwan and Singapore, where traffic crashes often seem to follow a pattern. What do we see in these places, Chris?

Chris Barnes: Yes, this is quite an interesting pattern that my co-authors and I found. When my co-author Sam Yam, he's a professor at National University of Singapore, who was interested in the idea of soccer being a global phenomenon.

And so what we hypothesized and what we found empirically, was that there is a spike in car crashes, both in Singapore and Taiwan, following major soccer games that are played in Europe.

Shankar Vedantam: And presumably that's because the games in Europe are played at a time when it's presumably early morning and in Asia.

Chris Barnes: Exactly right. So the soccer games in Europe are played at reasonable times for people to watch in Europe, which are generally unreasonable times for people to watch in Asia. And soccer is probably not as popular per capita in Asia as it is in Europe, but there are a lot of people in Asia and many of them are soccer fans.

And from some of our preliminary surveys that we did, we found that a surprising number of people in Asia are staying up very late into the night or very early in the morning to watch these games live.

And this is unfortunately considerably cutting into the sleep that they get that night. It appears that as a result of that missed sleep, their risk of a car crash goes up. And so that's exactly what we observe in the data.

Shankar Vedantam: You studied taxi crashes with a large taxi company in Singapore and also another data set which tracked really all auto crashes in Taiwan over a period of a few years.

Chris Barnes: Exactly right. So we found the same general pattern in these two very different locations in Asia. And there's an interesting nuance on top of that as well, that the effect scales with the popularity of the soccer teams that are playing in Europe.

Shankar Vedantam: Wow.

Chris Barnes: So if those teams are more popular, then we see a larger spike in car crashes the next day in both Singapore and Taiwan.

Shankar Vedantam: When we hear tragic stories of people making grave mistakes as a consequence of sleep deprivation, it's tempting to believe that would never happen to us. That could never happen to us. But the tragic stories we hear are only extreme examples of a universal truth. Sleep deprivation can profoundly change our judgment and our behavior.

When we come back, the complex consequences of not getting enough sleep and what you can do about it.

You're listening to Hidden Brain. I'm Shankar Vedantam.



Shankar Vedantam: This is Hidden Brain, I'm Shankar Vedantam. How often do you lag through the day, tired and foggy, dreaming of the minute you'll hop into bed for some sleep? You tell yourself that you'll change things in your lifestyle to get more sleep on a regular basis. But that day never comes, and you find yourself stuck in cycles of chronic sleep deprivation.

At the University of Washington, Chris Barnes says that when most of us know the consequences of poor sleep, we underestimate how profoundly it can affect us.

Chris, we've all heard about how a lack of sleep can affect our physical health and even our mental health, but you say there are more insidious effects.

One unfolded in 2018 when World Cup soccer fans were gathered in Moscow, and it involves a driver named Chingus Anarbek Hulu. Shankar Vedantam: Paint me a picture of what happened that day, Chris.



Chris Barnes: So Hulu was a taxi driver driving in a pretty crowded environment because of the soccer game that was going on, and he suddenly veered onto a sidewalk and accelerated running his car into a crowd of people there. Immediately after plowing into the crowd of people, he exited his vehicle and fled the scene. He ran away.

Shankar Vedantam: Do we know what happened that day and how the accident came about and why he ran away, Chris?

Chris Barnes: Yes. An investigation and interview of Ulu indicates that he had been working for approximately 20 hours straight on shift, and he was clearly quite tired while he was driving.

According to his perspective, he was drifting off and was looking to allow a pedestrian to pass by, and then he says that he hit the accelerator instead of the brake. So he had intended to stop and had unfortunately done the opposite.

Shankar Vedantam: So what strikes me about the story, Chris, isn't that he just fell asleep at the wheel and ended up hurting lots of people, but that he made this split-second decision to flee the scene afterwards. In some ways, the story speaks to some of your research because you've studied how a poor night's sleep can damage our ability to make good decisions, can damage our judgment.

Chris Barnes: There's a large body of research to indicate that sleep deprivation undermines our decision-making in general. And I do have some research in this area. The general theme across this research is that we are much worse decision-makers when we are sleep deprived. This is especially the case for any decisions that we make that are non-routine, that are novel and you have to figure things out on the spot rather than simply enacting a previous decision. So I could imagine that an unexpected incident like a car crash or running into people would be a very novel situation in which you have to rapidly make a decision, and you are impaired in that decision process. So it's perhaps not surprising that people make poor decisions in these contexts.

Shankar Vedantam: So you've looked not just at how the quality of our work might suffer as a result of sleep deprivation, but also you've looked into the relationship between a lack of sleep and unethical conduct?

Chris Barnes: Yes. This was some of my favorite research that I've ever engaged with.

And the idea here is that people in the context of work are faced with many temptations. So you might have a temptation to cut some corners, maybe tell a small lie, maybe take credit for someone else's work, maybe blame somebody else for your mistakes. Whatever form of work you have, there's probably some form of unethical behavior that you could engage in that might have some personal benefit. Fortunately, most of the time, most of us are able to resist those temptations, and that's great. But there's clear evidence to indicate that when people are sleep deprived, their ability to exert self-control, their ability to resist impulsiveness and cave to those temptations is eroded. So we see that when people are sleep deprived, their likelihood of behaving unethically tends to go up. And what I find especially fascinating about this is that you can see the same person behaving more unethically or less unethically on different days based in part on how much and how well they slept the night before.

Shankar Vedantam: And when you see sleep deprivation, Chris, are we talking about an hour less of sleep, five hours less of sleep?

Chris Barnes: I think of this as a relatively continuous scale where you will get the worst results if you get zero hours of sleep, but even small amounts of lost sleep matter. There are some pretty compelling studies, some of my research, but also a much larger body of research, that finds that even an hour of lost sleep can have meaningful effects on outcomes that we care about, like workplace injuries or work engagement or moral awareness. There are even some nap studies that allow people an opportunity to have like a 10 or a 15 minute nap. And that amount of sleep is enough to move the needle on some important outcomes like performance. Some of my research indicates that when people are sleep deprived, their moral awareness is lower. So they're less likely to even appreciate that there's a moral aspect to the decision that they're making.

They just treat it as a non-moral type of decision rather than seeing the layers of nuance that are often entailed in a moral decision. So that their sleep deprivation sort of simplifies their decision process in a way that fails to engage their moral frameworks.

Shankar Vedantam: I want to talk about another overlooked consequence of sleep deprivation. In 2014, the ESPN sportscaster Courtney Cronin came on the fire for a live television appearance. Tell me what happened, Chris.

Chris Barnes: So she had called in to a live ESPN radio show. She's an ESPN sports analyst. Chris Barnes: And she was covering the NFL Combine in Indianapolis.

ESPN host, in tape: She joins us on the Home of the Bears ESPN 10 on the hotline.

Chris Barnes: And she was having some technical difficulties with her earbuds. And you can actually see in the recording that she was getting some very annoying feedback. And you can see the frustration mount on her face. And then at some point she rips out her earbuds and says an expletive live on the air.



Courtney Cronin: And then everybody else is kind of unfolded. All right (expletive bleeped).

Shankar Vedantam: So Courtney Cronin blamed this outburst on sleep deprivation, but at a larger level, Chris, can you talk about how a lack of sleep can make us turn molehills into mountains?

Chris Barnes: Sleep deprivation has some pretty powerful effects on moods and mood regulation. So we see that when people are sleep deprived, they tend to have higher levels of irritation and frustration and anger, sometimes higher levels of depression, and then emotional control becomes more difficult. And this is due in part to the way different parts of our brain work together, the prefrontal cortex and the amygdala and the way that they interact with each other, that self-regulation is less effective. So people's emotions tend to be a lot more lumpy and wavy and big, and exactly as you say, when we're sleep deprived, something that would normally be more of a molehill looks like more of a mountain. And so we get big emotional reactions when people are sleep deprived.

Shankar Vedantam: There's even some evidence that sleep deprivation may be connected to major disasters. On March 23, 25, the Texas-based oil company BP suffered one of the worst industrial disasters in history. Tell me what happened and how sleep might be implicated in what happened, Chris.

Chris Barnes: So they had overfilled one of their fuel towers, and one of the automated systems then vented some of this fuel, which was then ignited, causing an explosion, raining down this flaming fuel on the trailers of the employees down below, causing several fatalities and injuries as well. So when they later investigated what happened, one of the potential causal factors was about a month straight of 12-hour shifts for the employees who were involved. So this was a tremendous accumulation of sleep debt from missed sleep over this time period. It wasn't just the 12-hour days, but also the long commute. Some of these employees had two-hour commutes on top of these 12-hour days. So, there was a lot of missed sleep in the period leading up to the incident.

Shankar Vedantam: I mean, there were eventually 15 workers killed and 180 people injured. And according to the investigation, one of the people involved had had an accumulated sleep debt of 43 hours. That is just enormous, Chris.

Chris Barnes: Yes. So, this is why I'm a little skeptical when people say missing an hour or two or three is not a big deal, because it's not just that one or two or three hours, it's the accumulation of many such nights of sleep debt.

Shankar Vedantam: There was even a recent report that looked at the relationship between nuclear disaster and sleep deprivation. Tell me what this found.

Chris Barnes: So, it is perhaps not surprising that several of these events tend to occur very early in the morning. So, both Chernobyl and Three Mile Island, these events happened between 1.30 in the morning and 4 o'clock in the morning is sort of the most important timing of these events. And these are times at which people tend to be at a poor state of mind from their circadian rhythms, pushing them towards sleep. And when they are working these shifts, it means that they have a work shift that is misaligned with their own natural circadian rhythm, which tends to leave them sleep deprived. And these are very complicated systems that they're working with, which is especially a problem when there's something novel that occurs. So something goes wrong that doesn't typically go wrong, and now you have to figure out on the fly how to deal with this in a state in which you are impaired from sleep deprivation. So of all the times at which these disasters tend to occur, that is the most dangerous time. That's when we see that it has happened, at least in those particular events.

Shankar Vedantam: You know, many of us are sleep deprived, but we're not in charge of a nuclear plant. But of course, some people are in charge of a nuclear plant, and they have circadian rhythms, too.

Chris Barnes: Yes, they do. And unfortunately, these nuclear plants have to be operated 24 hours a day, which means some of these employees have to work at circadian unfriendly times, where their biological drive is to sleep. And instead, we have them wake and operate complicated machinery. And then they go home and their schedule says they should be sleeping, but their biological drive is to be awake and do waking activities. So when we have such circadian misalignment, not only are we less alert and less effective when we are trying to do waking activity, but our sleep then becomes much more challenging as well.

Shankar Vedantam: I want to talk about one other common source of sleep deprivation. On March 11, 2018, a sightseeing helicopter crashed into the East River off the Upper East Side of Manhattan. Five people ended up being killed. Tell me what happened and how sleep might be connected to the incident, Chris.

Chris Barnes: So, this was a pilot and five passengers taking a tour in New York City. So, they were flying near the Upper East Side, and there were witnesses that said this helicopter started going down fast as if it were going to land on firm ground, and unfortunately, it did land in the water and then capsized and turned over sideways, and the pilot was able to escape, but the passengers, they had multiple layers of harnesses, and they were unable to escape, so they all died, they all drowned.



Shankar Vedantam: When investigators try to find out what caused the crash, Chris, what did they find?

Chris Barnes: One of the passengers was turned sideways with his legs outside of the helicopter, which put his supplemental harness sort of dangling towards some of the flight controls. And so, he leaned back, and then suddenly leaned forward, and this pulled his supplemental harness against the fuel release control. That's what depowered the helicopter, such that it started its rapid descent.

Shankar Vedantam: So, clearly, this accident had a direct cause, but it was also potentially an indirect cause. The date of the crash was March 11, 2018, as I said. It was a Sunday, but it was also the start of daylight saving time in the United States. On that Sunday, the clocks in many parts of the country jumped forward by an hour overnight, meaning that people got one hour less of sleep. So it says 6 a.m.on your watch, but your body clock feels like it's still 5 a.m. What do we know, Chris, about the relationship between that last hour of sleep on daylight saving time weekend and accidents and crashes from nationwide data?

Chris Barnes: Well, there are several studies that examine this. Some of my favorite studies examine car crashes. So the initial study published in 1996 found an elevated probability of car crashes following that spring daylight transition with a noticeable increase in both crashes and traffic fatalities. There was a follow-up study in, I believe it was 2018, that basically replicated that pattern. So we see a very clear spike in car crashes following that spring transition into daylight saving time. One of my own papers looks at workplace injuries. And we deliberately study mining injuries based on the idea that mining occurs underground. So any changes in daylight pattern distribution would be parsed out of the study. So we examined about a half a million mining injuries over a 25-year period. And surprisingly, we found a spike on the Monday right after the change to daylight saving time of 5.6% in mining injuries and an even larger spike in injury severity as operationalized by number of lost workdays due to the incident.

Shankar Vedantam: Many of us don't get the recommended amount of sleep every night. We know it can affect our well-being, our memory, our mood. But what's more surprising is that a lack of sleep can cause poor decisions and even unethical behavior. The solution seems simple, sleep more.

But of course, if the solution were really that simple, the problem would be solved by now. When we come back, getting to the root of our problems with sleep. Also, in our companion episode on Hidden Brain Plus, we take a deep dive into the effects of sleep deprivation on leaders, managers and workplaces. Turns out, sleep and sleep deprivation are thought to be factors when you're deciding whether to work at a company or to invest in one. If you're a manager or a leader, you need to hear how sleep can affect your judgment and decision making.

If you're already a subscriber, that episode is available right now in this podcast feed. It's titled, How Sleep Deprivation Affects Leaders. If you're not yet subscribed, please sign up at support.hiddenbrain.org. If you're using an Apple device, go to apple.co. slash hiddenbrain. You'll instantly have access to all our subscriber-only content, and your support helps to sustain the reporting, writing and fact-checking behind every episode of the show. Again, that's support.hiddenbrain.org or apple.co.slash hiddenbrain. You're listening to Hidden Brain.

I'm Shankar Vedantam.



Shankar Vedantam: This is Hidden Brain. I'm Shankar Vedantam. Do you have questions or comments about sleep and how it affects your life? Do you have a personal story about the effects of sleep deprivation that you would be willing to share with the Hidden Brain audience? If so, please find a very quiet room and record a voice memo on your phone. Two or three minutes is plenty. Email the audio file to us using the address feedback at hiddenbrain.org. Use the subject line, sleep. Again, that email address is feedback at hiddenbrain.org.

We often think of sleep deprivation as a personal problem, something that affects how we feel, how productive we are, how well we can get through the day. If we are tired or cranky from not getting enough rest, we assume the consequences will land on us.

At the University of Washington, Chris Barnes studies the science of sleep and the effects of sleep deprivation. He says the stakes are far higher than we imagine.

When people are chronically exhausted, that doesn't just affect their own health. It can shape the safety of entire communities. Chris, how much sleep do most people require, and how much sleep do most people get?

Chris Barnes: So most of us need between seven and nine hours. Of course, people hear that and they hear, oh, okay, seven is fine. So you might be one of the people who need seven, but you might be one of the people who needs nine. So most of us are in that range, seven to nine. For school-aged children, ten or maybe even more for the youngest school-aged children would be best. Unfortunately, neither children nor adults are typically getting as much sleep as they should. Almost all of those people who are sleeping six hours need more than six hours. Most of them probably need seven to nine like everyone else. Unfortunately, a large number of people believe they are short sleep superheroes, and that maybe it's fine for everyone else to get eight hours of sleep, but I'll be just totally fine if I get four hours of sleep, because I'm somehow above the need for sleep. It's an unfortunately common belief.

Shankar Vedantam: Can you talk about the importance of not just enough sleep, but of getting deep sleep?

Chris Barnes: Yes. When I talk about sleep, I usually talk about both sleep duration as well as sleep quality. Sleep quality is a little bit harder to understand, but the central aspect there is getting into really deep sleep. The simplest way to think about deep sleep is if it's difficult to wake you out of that sleep, that's a good indication, at least on the surface level, that you're getting to that deep sleep. We can really divide our states into three states. There's waking, there is REM sleep, rapid eye movement sleep, and there's non-rapid eye movement sleep. When we get to this deep N3 non-rapid eye movement sleep, there are some very important recovery processes that happen more so during that aspect of sleep than during REM sleep or waking activity. I do say that both REM sleep and deep non-REM sleep are both quite important, but that deep non-REM sleep can be kind of hard to get sometimes.

Shankar Vedantam: Let's talk about some interventions that can help us improve our sleep. Perhaps we should start by talking about the relationship that many of us have with our phones.

Chris Barnes: Yes, our phones are amazing devices that have lots of beneficial effects and increasingly clearly some harmful effects as well. So my colleagues and I conducted a study in which we examined smartphone use late at night.

We find that using these devices late at night tends to come at the cost of sleep and as a result, people go to work the next day, tired and they're not their best selves, and they tend to be less engaged at work the next day. So there is sort of an ironic effect here where you might be trying to squeeze in a little bit more work late at night on your phone, but then you work less the next day as a result.

So there's not really a net gain there, but there is a net loss to your sleep, and of course all the bad things that happen when you get less sleep.

Shankar Vedantam: So you and others have also done research on the use of blue light filters. Talk about this work, Chris. Does it help us when it comes to using our phones late at night?

Chris Barnes: The ideal solution here is not to use our phones late at night, but it is good to have some other tools that can help to mitigate some of these effects. Blue light unfortunately suppresses the production of melatonin, which is a chemical that is useful in the process of falling asleep. So when we are using our phones right next to our face, shining that blue light into our eyes, we're essentially sending a signal to our bodies to stay awake. So one way to deal with this is to put on glasses that filter out that blue light, which has the most powerful effect on circadian system. So if that blue light doesn't reach your eyeballs, then it won't have as much of an effect. So I want to be careful to note that these blue light filtering glasses are not a magic bullet. They are not going to fully solve the problem, but the data do indicate that they can be a useful partial solution to some of the circadian dysregulation issues that we tend to face in our modern society.

Shankar Vedantam: I'm wondering if you can address an elephant in the room here, Chris. One of the cultural undercurrents, especially in American society, is that people who are high status often claim that they need less sleep or they're getting less sleep. And in some ways it sends a message to everyone else that being sleep-deprived is in some ways a sign of being important. Can you talk a little bit about this and how in some ways that message runs very counter to the message that you are preaching?

Chris Barnes: Yes, so there is an idea floating around out there that if I'm really important, then I don't have time to sleep and that if I am especially capable, that I have less need for sleep.