In this video I describe the effects of sleep deprivation. Sleep is about more than just rest, recovery, and energy conservation and it plays an important role in memory consolidation and integration of our experiences into a coherent sense of self. Sleep deprivation can occur as either chronic sleep deprivation or as acute sleep deprivation. Physical effects include fatigue, dark circles under the eyes, hormone fluctuations, and reduced physical performance. Chronic sleep deprivation is also associated with obesity, likely to due fluctuations in ghrelin, leptin, and cortisol. Cognitive effects of sleep deprivation include impairments in concentration, attention, judgment, memory, coordination, and reaction time.
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Video Transcript
Hi, I’m Michael Corayer and this is Psych Exam Review. In this video we’re going to look at some of the effects of sleep deprivation. Now we spend about a third of our lives sleeping so this should tell us that sleep is pretty important right? There’s some vital functions that need to occur and they occur during sleep. Now you might think of sleep as just being about rest and recovery or maybe conserving our energy but that’s not really an adequate explanation for why we spend so much time sleeping.
One way that we can see this is the fact that if you conserve your energy, let’s say that you sit on the couch all day and you don’t really expend much energy and you eat a lot of food, right? You would think, well then maybe you would need to sleep less but in fact that’s not the case. You probably know you still get tired and you still need to sleep even though you aren’t using a lot of energy and even though you’re not really recovering from anything. So there’s other processes that must be occurring during sleep which are important and one of these seems to be memory consolidation. So sleep seems to be a time in which we integrate our new experiences into our existing memories we sort of form a coherent sense of self and understanding of the world.
And so sleep seems to be part of the time in which we sift through our experiences we try to make sense of them right? We extract the gist, right? Where we find the meaning of things because we don’t simply recall a list of facts. We recall things in terms of their meaning to us and how they help us to understand our life and understand maybe what we should do in the future. And so sleep seems to be a vital part of this process and one way that we can see this is the fact that babies spend a lot more time sleeping. This makes sense because babies have a lot more to figure out, right? They have lots of new experiences every day and they need to make sense of all of this information. Whereas when you’re an adult you kind of have made sense of a lot of things already you don’t have as many new experiences every day so you have less to kind of figure out and you don’t spend as much time sleeping as a baby does.
Now we also see this and that babies don’t just spend more time sleeping, they spend more time in REM sleep and this indicates that is an important part of this memory consolidation process. We also see this in that people who are under lots of stress also spend more of their sleep time in the REM state. This indicates that REM is part of this sifting and searching through our experiences to extract the meaning and figure out how should this inform my future behavior, how can this fit in with my previous experiences? So when you’re under some stressful circumstances that’s what you’re really trying to do, you’re trying to figure out what it means and how to make sense of it and REM seems to be helpful in getting you to do that. Ok, so when we think about sleep deprivation there’s two main types we can think of sleep deprivation as either being chronic or acute. So chronic sleep deprivation refers to not getting enough sleep over an extended period of time and this is probably what you’re likely to experience, especially if you’re a student if you’re staying up late to finish assignments and you’re waking up earlier than you want to to go to class. You might experience chronic sleep deprivation where you’re only sleeping for four or five hours each night for several nights in a row, especially if it’s like exam period at your school. So you also probably know that eventually you have to repay this sleep debt that you accumulate and you probably do this on the weekends, where you might sleep for 12 or 14 hours continuously and that’s trying to make up for this lack of sleep that you had before this chronic sleep deprivation.
Now there’s also acute sleep deprivation and acute sleep deprivation refers to staying awake continuously. And this is obviously going to be a bit shorter in duration. So you might have chronic sleep deprivation that lasts for, you know, over the course of a whole week. You might have many nights in a row you don’t get enough sleep, whereas acute sleep deprivation you might stay awake for an entire night or maybe too nights and at a certain point you’ll probably crash and you’ll basically just have to sleep. Now i think the world record for cute sleep deprivation is somewhere around 11 days, which is quite impressive but at this point the guy who was doing this had hallucinations and seemed to be almost dreaming while he was still awake.
Now there are some people who sleep who stay awake even longer than that and these are people with a rare disorder called fatal familial insomnia. So what happens is, this is a prion disease, so prions are misfolded proteins that accumulate, and what happens is these proteins destroy parts of the brain. In fatal familial insomnia the parts of the brain that they damage seem to be associated with initiating the sleep state or allowing you to enter from waking to the sleep state. And so if you destroy areas responsible for these processes you can no longer enter the sleep state. So people who have this disorder are not able to fall asleep even though they’re obviously incredibly tired. And so what happens is they stay awake continuously, after a few weeks I mean they’re a total mess, you know, they’re really unable to function at all but they stay awake continuously for several months, at which point they die because you need to sleep. And this helps demonstrate this and it’s why it’s called fatal familial insomnia.
Ok, so that’s an extreme case of acute sleep deprivation. We can also have sleep deprivation that occurs specifically. We can deprive people of only REM sleep. So the way that we do this is if we have some participants in a sleep lab and you know they are connected to an EEG and we watch their brainwaves and we can see okay they’re in slow-wave sleep and then when they enter the REM state, we wake them up and then we let them go back to sleep. And we watch the EEG and we see that okay they are starting to enter REM again, we wake them up again. You do this repeatedly throughout the night and maybe even for several nights in a row. So the person is getting slow-wave sleep, so any processes that occur during slow-wave sleep you know we can assume are happening but they aren’t getting any REM. We can see the importance of REM because if you do this if you have this selective REM deprivation then you allow them to sleep normally you get what’s called a “REM rebound effect” where they spend lots of time in REM after this, right? And so this shows the importance of REM that you can’t get rid of it, you can’t deprive somebody of REM over a long time. They need to have REM and in the future they’ll end up sleeping though spending more of their sleep time in REM. Ok, so let’s take a look at some of the effects of sleep deprivation and I’m mostly going to refer to the effects of chronic sleep deprivation although these also apply to acute sleep deprivation.
But in the case of chronic sleep deprivation this is probably what you usually experience. I mean if you force yourself to stay awake for a long period of time with acute sleep deprivation eventually you’ll just have to sleep right and this might happen within a day or two you probably don’t frequently stay awake for more than a day at once, you know, even if you have an all-nighter while you’re working on a paper or something. Whereas chronic sleep deprivation you might experience much more often. Ok, so what are the things that happen when you’re deprived of sleep?
Well you’ve probably experienced sleep deprivation so you probably already know these but let’s go through this list and see if these are familiar to you. Ok, so the physical effects of sleep deprivation. The first is the obvious one that you definitely know and that’s that you feel tired, you know, you experience fatigue when you aren’t getting enough sleep, right? Another thing that happens is that you get dark circles under your eyes. You might wonder what is that, you know? How is that happening? How is it that you have someone, you can look at somebody and tell that they aren’t getting enough sleep just by their eyes. So what is going on there?
Well, what’s happening is that when you don’t get enough sleep the skin underneath your eyes, this is some of the thinnest skin in your body, it becomes a little bit paler when you’re not getting enough sleep. And so what happens, you’re actually seeing the blood vessels underneath that skin and that’s why you appear to have these dark circles, you’re able to see those blood vessels because the skin is a little bit paler than it would be. Ok, so that’s another physical effect of sleep deprivation.
Then we have some hormone fluctuations and I’m going to talk about some of these specifically in a second but not getting enough sleep influences levels of different hormones in your body. So we have hormone fluctuations. And then lastly, and again you probably already know this, you have reduced physical performance and this is on a number of different types of tasks. And of course, you know if if you’re an athlete or something, I mean or even if you’re not you probably logically know that if you have a big game or a big meet or something you need to get enough sleep beforehand if you want to perform at your best. If you haven’t gotten enough sleep the night before or in the several days before this event you’re not going to perform at your best. You’re not going to set any, you know, personal bests or, you know, new records when you’re deprived of sleep because your physical performance is reduced. You’re not as strong, you’re not able to run as fast, all of these things.
Ok, so I want to look at one specific interaction of these hormone fluctuations because this refers specifically to chronic sleep deprivation. So in the case of chronic sleep deprivation, it’s associated with obesity. Now it’s not the case that being chronically sleep-deprived definitely causes obesity, obviously it’s more complicated than that. And it’s also the case that obesity can actually cause chronic sleep deprivation. There are certain sleep disorders which I’ll talk about in the next video like sleep apnea and if you are obese you’re more likely to suffer from sleep apnea. And if you suffer from sleep apnea that’s going to disrupt your sleep, you’re going to be more likely to be sleep deprived because the sleep apnea causes you to repeatedly wake up throughout the night and so as a result you know being obese puts you at greater risk for being sleep deprived and being sleep-deprived also increases your risk of obesity. So why is that?
Well, there’s a couple things that happen. It has to do with these hormone fluctuations when you are chronically sleep-deprived a hormone called ghrelin is increased in your body and ghrelin signals hunger. You can remember that if you think of ghrelin and your stomach growling, so ghrelin makes you hungry and when you’re sleep deprived you have increased levels of ghrelin that means you’re going to be experiencing more hunger. So that probably causes you to eat more. Not only that, but you have a decrease in the hormone leptin. So what is leptin? Leptin indicates satiety ,meaning leptin tells you when you feel full right? When you’re eating a meal eventually you get to a point where you don’t want to eat anymore, right? That’s this satiety point. You feel full, you don’t want to eat anymore. That’s partly signaled by this hormone leptin and when you’re sleep deprived your leptin level goes down. That means you’ll eat more before you realize you’re full. So this is a bad combination, right? You have more cravings for food and you tend to eat more, and making things even worse you have reduced willpower right? You feel less sense of control over your own behavior when you’re deprived of sleep and so when you get those cravings you’re more likely to give in to them.
All right, it’s going to be harder to resist and not only this but we also have an increase in another hormone called cortisol. Cortisol, the stress hormone, you may have heard of it before and we’ll go into a lot more detail on stress in a future unit but for now we’ll just say that one of the things that cortisol does is it encourages your body to store fat, right? It encourages fat to be mobilized into fat cells and particularly in the abdominal region. So obviously that’s going to be associated with obesity, if you’re storing more body fat in your abdomen.
Another thing that cortisol does is it suppresses your immune system, and again we’ll talk about exactly why and how this happens in a future unit but this is why you probably know if you are chronically sleep-deprived you’re more likely to get sick, right? Because your immune function is decreased when you’re deprived of sleep and this also explains why when you are sick you probably spend more time sleeping because you’re trying to activate your immune system, right? You don’t want to be you know sick and also sleep-deprived. So when you’re sick you tend to be more tired and you tend to hopefully you have a chance to sleep more and that’s to encourage your immune system to be activated. Ok, so those are some physical effects of sleep deprivation we also have cognitive effects and these again you’re probably familiar with a lot of these so I’m not going to go into a lot of detail on each of these.
But what are the things that are impaired when you aren’t getting enough sleep in terms of your cognition? And obviously there’s some overlap between physical and cognitive effects. Well, all of these things are going to be impaired; your concentration is impaired, your memory is going to be impaired, your judgment is impaired, your coordination. So you could think of that as partly physical and partly cognitive.
We have your attention, your ability to stay focused again, overlap with some concentration, there that’s going to be impaired. And maybe the most important one is that your reaction time is reduced. You can’t respond as quickly to things when you’re deprived of sleep and I’m going to post a link in the video description where you can try this out. There’s a task it simulates sort of a driving task and have to press a button really quickly when something appears on the road. And what you can do, what I recommend trying is, do this when you’re feeling alert when you’ve gotten a good night’s sleep and try it again when you’re tired. You know, when you haven’t got enough sleep or you stayed up really late the night before. You’re feeling a little drowsy and try this task again and you’ll see that your reaction time is reduced, you can’t seem to be as fast at the task. So this brings us to consider it something that I’m going to talk about in more detail in the future video which is “drowsy driving” and it’s similar to drunk driving in terms of the impairments that occur. So if you haven’t slept in 24 hours or something and you’re driving a car it’s similar to being drunk and drowsy driving is a big problem. It’s estimated that about 100,000 accidents occur as a result of drowsy driving in the US every year and from those an estimated 1,500 people die. So this is a really really important topic and I want to address it in a little more detail in a future video but for now, suffice to say, don’t drive when you’re tired.
If you’re feeling drowsy, you know, pull over, take a nap, you know. Arrive late for wherever it is you’re supposed to be going to. It’s simply not worth it to drive when you’re drowsy because of all of these negative effects here; your reaction time’s impaired, your concentration is impaired, your judgment is impaired and this can have catastrophic consequences. Ok, I hope you found this helpful, if so, please like the video and subscribe to the channel for more. Thanks for watching!
