Written by Christopher Kelly
Nov. 22, 2019
[0:00:00]
Christopher: Well, Greg, thank you so much for joining me this morning. We're going to talk about insomnia. How are you feeling?
Greg: I'm feeling mostly bad. I actually had a little bit of sleep maintenance insomnia last night. I'm not even kidding.
Christopher: Do you know what? I read your mind. It's funny, isn't it? I used to have the most terrible insomnia, and now I don't. I sleep really well but still, occasionally, that happens. I can't get to sleep. I can't stay asleep. It's not something I've completely solved. Is that normal? How common is insomnia?
Greg: It's difficult to say precisely how common it is, but it seems like at a given time, about a third to half of adults experience some sort of acute or adjustment insomnia. Maybe there's some triggering event in their lives. Maybe they're stressed at work, for instance, or maybe they're very excited about something that's coming up. That can temporarily interfere with their sleep. More chronic insomnia might affect something like ten to 15% of adults at a given time.
Christopher: What's the outcome for these people? Is it associated with worse health outcomes?
Greg: It's associated with a few things. If you look at health care expenditures, for example, when people have insomnia, they're more likely to use those resources. They're more likely to visit their physicians. They tend to experience work-related problems. They're more likely to be absent from work, for example. Presenteeism is probably higher among people who have insomnia.
They're more likely to make errors at work or have accidents. They're more likely to have more serious road accidents. Also, more troublingly, they're at higher risk for things like suicide. They tend to abuse substances more commonly, and there seem to be some associations between insomnia and immune dysfunction too.
Of course there are lots of comorbid conditions too. If you look at people who have chronic pain, for example, perhaps 50 to 70% of those people will experience insomnia. People who have mood disorders such as depression and anxiety also tend to have much higher rates of insomnia than you would find in general population.
Christopher: Greg, you've been writing a wonderful series of articles for NBT, which I will of course link to from the show notes for this episode. If you poke around inside of your podcast, you will surely find the show notes and Greg's series of articles will be linked from there.
I resist the temptation to go into excruciating detail here, but can you differentiate between acute and chronic insomnia?
Greg: Yeah. So, acute insomnia, as I've touched on, is just the presence of temporary difficulty sleeping. I should just mention that one core characteristic of insomnia is daytime dysfunction. If you don't experience some sort of daytime dysfunction, for example sleepiness or difficulty concentrating, then you don't really have insomnia. The definition of insomnia would be that type of daytime dysfunction plus some sort of sleep impairment, and that's given an adequate sleep opportunity.
There are many people who just don't spend enough time in bed and they therefore experience shorter sleep. That's not really insomnia. If you have enough time in bed but then you still find it hard to fall asleep or maybe once you're asleep, you wake up frequently and for long periods, or you find it hard to get enough sleep, or you just feel like you didn't sleep very well then you have some form of insomnia.
Interestingly, clinicians don't tend to put hardly merit guidelines on those. For example, there's a type of insomnia called sleep onset insomnia where people find it hard to fall asleep initially. It's not like we can say, if you don't fall asleep within 30 minutes of trying to fall asleep then you have sleep onset insomnia. There's always that subjective component.
With that said, there are different types of insomnia. There's the type of acute insomnia that you mentioned which is always in association with some sort of identifiable stressor. That might be something physical. It might be some sort of environmental disturbance such as lab noise, for instance. This tends to be of short duration. Perhaps it lasts days to weeks, and you'd expect it to resolve when the stressor is withdrawn.
Then you have these more chronic insomnia too, and those are subdivided into two broad categories or three broad categories really. One would be insomnia with associated other sleep disorders. For example, maybe somebody has obstructive sleep apnea where their upper airway temporarily collapses at night, starving them temporarily of oxygen.
You have insomnia that is due to medical disorders or drug use, for instance. An example of a medical disorder might be rheumatism or thyroid problems. It could be either hypothyroidism or hyperthyroidism.
[0:05:03]
You have primary insomnia, and there are three types of those. One is psychophysiological. One is called idiopathic which typically has its onset very early in life, and those poor people will tend to experience very long periods of insomnia and very rare periods of remission from their insomnia.
There's another type called paradoxical insomnia which is characterized by sleep state misperception. These people feel like they spend next to no time asleep but interestingly, if you then measure their sleep objectively using something like polysomnography, they actually spend a considerable amount of time asleep. In that way it's paradoxical.
Christopher: What might be going on there? I guess it's a paradox. You don't know.
Greg: Yeah, it's a good question. I don't feel like I'm in a good position to give you a good answer to it.
Christopher: Okay. Let's move on then. I think for most people listening, they will be sold on the importance of sleep at this point. I don't think there's anyone listening that's thinking, maybe I should get a little bit more sleep. Perhaps four hours is not enough. There's just no one listening like that. Everybody is at least allowing, say, eight hours. Would you agree? Is there some minimum threshold below which you say, you're just not allowing enough time to sleep?
Greg: If you look at the National Sleep Foundation guidelines for 18 to 64-year-old adults, they recommend seven to nine hours of sleep per night. Obviously we're not asleep 100% of the time that we're in bed. People who have healthy sleep are typically asleep for at least 85% of the time that they're in bed. So if you wanted to get seven to nine hours of actual sleep, you need to spend a little bit more time in bed than that.
With that said, there are genetic differences in sleep duration. Interestingly, there's a paper published very recently which identified the genetically shorter sleepers that we found to date and, on average, people who carry that particular genetic mutation seem to need about 5.7 hours of sleep per night. So, those are the shorter sleepers.
Christopher: Wow, that will crash me in about three days.
Greg: Yeah, crash me in one night I think. So those are the shorter sleepers that we know of. With that said, most people probably need seven to nine hours of sleep per night, and the amount of sleep that you need is a moving target. For example, you're undergoing strenuous exercise training then perhaps you need a bit more than normal. If you're fighting a chronic infection then you might need a bit more. Also, you'll probably find that if you live at a relatively high latitude then you need a bit more sleep during the long nights of winter than you do during the short nights of summer.
Christopher: I had not thought of that. That's a good point.
Greg: Yeah, Ken Wright did some lovely camping experiments on that. Basically they compared the data they collected during the summer to those that they collected during the winter, and they found that the duration of melatonin synthesis and the total sleep duration quite closely tracked the total period.
Christopher: Interesting. I will of course link to everything that Greg is mentioning in the show notes for this episode. So, what should people do? They're allowing enough time for the sleep to happen. They know they're not sleeping very well because they don't feel good the next day. They're noticing some sort of impairment or maybe just feeling damn tired. Where do you start trying to figure out what's going on? Would you recommend sleep tracking for those people?
Greg: Yes, in short, and I think it's useful for everybody to track their sleep from time to time. Certainly when it comes to insomnia, that's always the first protocol. What you typically do is have people track their sleep for two weeks but baseline, and there are different ways to do that. You could, for example, use a wearable, but I think it's particularly useful for people to use a sleep diary because, as I mentioned, people's subjective experiences of their sleep are important too. There's a useful online diary at thebettersleepproject.com that people can check out.
In those diaries you record things like the time at which you go to bed, how long it then takes you to fall asleep, how many times you wake up during the evening, how long, in total, you're awake for during the evening, the final time that you wake up in the morning, the time that you get out of bed in the morning, how you feel when you slept and so on. Once you've done that you can establish what your baseline sleep is like. Then as you start to intervene to try and improve your sleep, you can work out whether the changes that you've made are positively or negatively affecting your sleep.
Christopher: Do you not feel that there's something you might call -- a neurologist friend, Josh Turknett, talks about the Heisenberg uncertainty principle when it comes to sleep. The idea is that you can't really track the thing without changing the thing. I know that's the case for me when I wear any kind of device that tracks sleep. I find myself lying awake in bed wondering what my sleep tracker is going to tell me about my sleep the next day. Obviously that's counterproductive. Is that uncommon? You obviously still recommend tracking.
[0:10:18]
Greg: Yeah, I still recommend tracking. I don't think that is uncommon. I also don't think that we have a strong understanding of the prevalence of that type of response to tracking. Something I mentioned is that people who have insomnia tend to have this attentional bias to sleep-related use. They spend the whole time thinking about sleep. They think, oh, if I stay out tonight and see friends then that's going to interfere with my sleep opportunity tonight, and tomorrow I'm going to be even more fatigued. We'll come to this later, but that's one of the reasons that they need to realign themselves with what they value most in their lives. As they start to do that, they will start to adjust their behaviors accordingly.
Something to mention which you touched on earlier is that people who have insomnia actually often give themselves plenty of time in bed. They actually tend to spend more time in bed if anything. It's just that their sleep becomes enormously inefficient. The problem is that because they're spending so long in bed awake, they condition themselves to associate their beds with being a place of wakefulness. What they need to do is they need to retrain their brains to associate the stimulus, namely the bed, with the behavior, namely sleep. If you look at some of the core therapies that are used to help people who have different types of insomnia, they center on reestablishing that association between the bed and sleep.
Christopher: Yes, of course, and you went into detail in the articles. Now I first became familiar with that idea when I first interviewed Dr. Ashley Mason who was really good at talking about that stuff. I really enjoyed that interview too. Let me ask you this. So last night you didn't sleep that great. How do you handle it?
The way that I handle it now is that I know that the next night I'm going to have really awesome sleep, so the sleep deprivation from night one creates additional sleep pressure that leads to an awesome night of sleep on night two. Someone with a PhD in sleep physiology may be going to tell me that's nonsense, but I find that argument convincing enough to where it works for me quite consistently.
Things happen in everybody's life. For example,a cyclocross race is really good at inducing insomnia. I know the night after, I'll sleep really good. Let me ask you two questions. First of all, is that nonsense, my thinking? Secondly, how do you handle a night of shitty sleep?
Greg: It absolutely isn't nonsense. If you look at the core therapies for insomnia, the behavioral therapies all involve some form of sleep restriction. The idea you allude to is to build that sleep pressure during the daytime such that when the person does go to bed, there's this overwhelming pressure to sleep, and therefore they sleep much more efficiently as a result. That's in conjunction with very consistent times in bed rather than having very variable bedtimes. That type of bedtime variability and sleep variability do actually associate with different health problems.
So, that makes complete sense to me that if you lose some sleep one night then the next day you should sleep better, provided that you don't then go and try and medicate yourself out of that sleep pressure. Because what will many people do, they'll reach for an extra cup of coffee or two. Coffee, of course, contains caffeine which is an adenosine receptor antagonist. Adenosine is probably the main biological correlate of that sleep pressure. So if you can avoid the temptation to reach for extra stimulation, whether it's from caffeine or nicotine or anything else, and give yourself an adequate sleep opportunity the next evening, perhaps not necessarily go to bed substantially earlier.
That's a problem that is common in insomnia. People will lose the ability to accurately sense their own sleepiness. They'll think, it's 11 pm, I need to be in bed. What happens is there's this imbalance in their bodies between arousal and sleepiness. They're still very aroused, cognitively. There's no way they're going to fall asleep even if it's 11 pm. What they need to do is start to better understand those internal sensations of sleepiness and then start to only go to bed when they are sleepy. That's one of the reasons that mindfulness meditation holds a lot of promise in helping these people because people's interoception, that ability to sense their internal states, tends to improve with that type of mindfulness training.
So, that's the long answer to your first question. The second question, what do I do? Well, because I never have difficulty falling asleep unless, for example, I have a very big meal very late in the night or if I have lots of caffeine late in the day. I consume very little caffeine actually because I tend to have difficulty staying asleep if anything. Especially if I feel stressed because of work-related stress, for instance, or maybe I'm pushing myself too hard in the gym then I will apply the so-called 20-minute rule. If I wake up in the night and I've been awake for roughly 20 minutes -- I mention here that you never want to start watching the clock.
[0:15:36]
Christopher: I was going to say, how the hell do you do that?
Greg: Yeah, you have to just go by some sort of internal timing mechanism because one of the things that characterizes people who have insomnia is that type of clock-watching anxiety. For that reason, it's useful for them to get those devices out of their bedrooms.
If you feel like you've been awake for roughly 20 minutes or so and you don't think that you're going to fall back asleep imminently then you should leave your bedroom and go and do something that's very relaxing in dim lighting in another room. You want to make that process as straightforward as possible because let's say, for example, that you have insomnia and you're going through bedtime restriction therapy, which we'll get to later, but basically these people who spend lots of time in bed but don't spend much time asleep, will restrict their time in bed to build that sleep pressure which will then make their sleep much more efficient. Over time, provided their sleep is efficient, they will extend their time in bed and then they will start to return to a much healthier sleep pattern.
So, if you're experiencing that problem, even if you have that restricted time in bed, after 20 minutes you would leave your bedroom, which is going to be really hard. Let's say you've got six hours in bed in total because you're going through bedtime restriction therapy, and now you have to get up out of your bedroom and do something relaxing in a different room. People don't want to do that, so you've got to make that process easy. Therefore you should do things like making the other room comfortable. Perhaps you leave the radiator on overnight if you live in a cold place, for instance. Perhaps you leave a very dim light on in a corner so that your path is unimpeded and so on. Then do something relaxing.
When I say, do something relaxing, I don't mean pull out your phone because what you can do is you can condition yourself to become aroused at certain times of the evening. You actually see this with medication used in insomnia. In some instances people will be prescribed hypnotics or sleep-promoting drugs, and some people will mistakenly start to use these if they start waking up during the night on an as-needed basis. The problem is they then train their brains that if they wake up at this time, they can take their sleep drug and then sleep better, so they end up waking more frequently at that time. Likewise, if you find social media very compelling, for instance, when you wake up in the evening and then go into your quiet room next door to do something relaxing, you start wiping through Instagram, you'll probably condition yourself to wake up at that time.
So, it needs to be relaxing, but it should probably also be somewhat boring. Examples of that might be reading a not particularly stimulating book. It could be listening to a podcast that isn't riveting. Obviously that rules out NBT.
Christopher: Yeah, you're not listening to this one.
Greg: Or it could be meditating which is probably my preferred choice actually. Somebody could just do a simple breathing meditation. Because while one of the core ways in addressing people who have insomnia is through targeting their behaviors through things like bedtime restriction and stimulus control which I touched on earlier, it's what I was speaking about when I was talking about the need to recreate association between the bed and sleep, what these people need to do is also start to engage in these relaxing activities. These consistently do help people who have insomnia. One of these is meditation, perfect thing to do at this time.
Another is progressive muscle relaxation. If you look at people who have anxiety, they often have increased muscle tension in certain muscles. Maybe, for example, they keep their shoulders shrugged, and they have lots of activity in their upper trapezius muscles. If that's the case then the thinking is that if these people can sequentially tense muscles, hold the tension and then relax the muscles, by inducing that relaxation, they will have the opposite effect of also reducing anxiety in the process. During that type of progressive muscle relaxation, somebody will scan through the body. They might start with their toes and then slowly move up through their lower legs, through their upper legs, through the pelvic region and then into the torso and then the arms and then finally the head and the face. That can be very useful for those people at that time too.
[0:20:11]
Another type of relaxation which lots of people benefit from is visualization. That's really helpful for people who are particularly highly attuned to their bodily sensations. If you're one of those people who really feel your heart pounding while you're in bed during these bouts of insomnia, and this is very common among people who have insomnia, then visualization can help you temporarily escape those sensations. What you want to do is basically transport yourself to a scene that you find very relaxing. You want to practice this during the daytime before experiencing it during the sleep period so you can get good at it first and then you can call on that place of happy relaxation when you need it.
The goal in these sessions when you train yourself to become better at visualization should be to make the scene as vivid as possible. Whereabouts are you? Who are you with? What can you see? What can you taste? What can you feel on your skin? Is it warm? What can you hear? As you can start to make that scene vivid, you can call on [0:21:20] [Indiscernible] times and that tends to help people fall asleep faster too.
One more thing to mention is music therapy which sounds somewhat silly to some people, but actually if you look at all the studies that have been done then spending perhaps 25 minutes to an hour listening to relaxing music, three to five times a week, consistently helps people who have insomnia. So, pick some music that you find relaxing, listen to it perhaps shortly before bed. You could also listen to it at that time that you wake up during the night. Just don't listen to heavy metal or techno.
Christopher: I was going to say I was thinking of maybe Prodigy.
Greg: The Firestarter.
Christopher: The Fat of the Land should be good, yeah, Firestarter, perfect. So, one would assume then if one of these things is good then all of them would be better and that maybe I should just set up a little circuit in my house so that when I wake up in the middle of the night, get up and just spend 20 minutes on each station. Is that right?
Greg: I would say that if somebody is very attuned to their bodily sensations, they can feel their heart pounding or they're listening carefully to their breath or they can hear things much more acutely at night because in general the environment is quieter then try visualization. If you are struggling with insomnia as a result of anxiety then I'd probably try progressive muscle relaxation. I'd probably use that also if people have bodily discomfort. Otherwise you can give some of the other options a go.
There's one more cognitive therapy that's commonly used in this type of situation which is called paradoxical intention which is actually popularized by Viktor Frankl who is the guy that wrote Man's Search for Meaning, which I'm guessing about three-quarters of the lessons you've probably read.
Christopher: I think I was actually the last person who found out about that book. Every single person I say to, "Have you read Man's Search for Meaning," they're like, "Yeah, of course, who hasn't read that?" I was literally the last person to read it, I think.
Greg: What he did there is you confront your negative sleep-related thoughts, head on, and one way of doing that will be to get yourself to try and stay awake a little bit longer, recognizing that if you do stay awake a bit longer, it's probably not going to be massively detrimental for your function the next day as much as people who have insomnia seem to think that's the case. So you might lay in bed when you go back to bed and open your eyes gently, obviously the room will be dark, and say to yourself in your head, just stay awake a little bit longer, just a little bit longer. As that continues, you congratulate yourself for sustaining that wakefulness. What you'll probably find is that you wake up a few hours later and you'll think how rubbish you were at maintaining that wakefulness because you're also basically just boring yourself to sleep. So that tends to be quite effective for people who then return to bed and still can't quite drop off. That's one more strategy that people can use.
Christopher: What worked for you last night?
Greg: I came to the living room, and I just read a little bit in very dim lighting. I'm reading Homo Deus at the moment which is actually quite stimulating, but it wasn't stimulating enough to keep me up for too long. I was up for maybe an hour and 15 minutes in the middle of the night but then when I fell back asleep, I stayed asleep actually fine.
[0:25:00]
Christopher: That's interesting. It's not as good as Sapiens, is it?
Greg: It's not, no. I read them in the wrong order actually. I started Sapiens and then I read 21 Lessons. Now I'm reading Homo Deus. I read them in the order in which they go through history, past, present, future, but obviously they're released past, future, present. Yeah, just read the first book, that's what I would say to people.
Christopher: Yeah, I would totally agree with that. I want to get onto talking about furniture specifically the bed. Before we get there, I wanted to talk to you about metabolism. I feel like my insomnia in the early days, looks like circa 2011, was in part caused by my inability to kick off what you might call the fasted state. I just was so dependent on glucose that I had literally no ability to tap into fat reserves and so when I woke up in the middle of the night, I was super stimulated and aroused.
Now, if I wake up in the night, I'm really quite happy just to lie there and just be still. There's no motivation to get up and do anything. Whereas before, I had to get up and do something. It would drive me insane like skin itching. I'd just got to get out of bed. I was starving hungry. I wanted to go and eat another big box of breakfast cereal which I regularly did which brings me to another important point which Ashley Mason mentioned and you just mentioned as well is the thing that initially starts the problem is not necessarily the thing that perpetuates the problem. You've got to watch out for that.
What do you think about the idea? I don't know. It's just based on my own personal experience. As Simon keeps telling me, you have to be really careful about personal experience, Chris, especially you in particular. So, what do you think? Do you think there are a bunch of people walking around that lack the ability to make it through the night because they just can't do the fasted state?
Greg: I think it's really hard to say at the moment. You will hear people talk about things like hypoglycemic episodes. I don't think that there are data that really show that that's a contributor to those nocturnal awakenings. Sometimes it's probably related to appetite dysregulation, [0:27:14] [Indiscernible], and what you should have in somebody who is healthy is this nice nocturnal peak in leptin synthesis. Leptin does have a circadian rhythm, and that's one of the factors that probably helps people stay asleep during the night.
If you're on a diet that contains lots of processed food and your appetite regulation is worse, then perhaps you're more likely to wake up at night hungry. Of course if you go for long periods of time in a state of negative energy balance, your body will want you to get up, to go out, try and acquire food to help you restore homeostasis. In that way, it's probably an evolutionarily based deductive mechanism for you to go out and seek food. There is, of course, more play, I'm sure, and one of those things probably relates to dysregulation in the synthetic nervous system.
For example, maybe your cortisol rhythm is off. Again you should have this very high amplitude cortisol rhythm. You should see this large spike in cortisol production around the time that you wake up in the morning. That alert in response will help do things like mobilize your energy reserves and increase your blood pressure and increase arousal for the day ahead. In insomnia, what sometimes happens is people have a flattened cortisol rhythm, and they'll have a flattened core body temperature rhythm too. Perhaps that relates to the inability to sleep through the night as well.
So, there are probably a few different things going on. I think a lot of it does come down to optimizing nutrition. If you look at typical recommendations related to insomnia, it's rarely the case that you'll see people talk about things like nutrition, but there are plenty of reasons to think that diet will influence sleep. Oftentimes, it's timing and composition.
If you touch on the timing alone, for instance, there has been some nice work recently showing that people who have very early dinners have more even appetite regulation perhaps counterintuitively. Also, consuming relatively small at dinner tends to increase parasympathetic nervous system during the sleep period which should be conducive to restorative sleep. So I think having an early-ish dinner, provided that the foods that you consume are satiating, makes a lot of sense for sleeping well. Diet composition, of course, will include sleep, so we can touch on all sorts of things there.
In your case, Chris, it was probably related in part to your diet choices, but I would say that almost all of the time also, if this is something that's recurring, it's likely due to other factors. Perhaps it's due to alcohol-intake, which I'm sure in your case it wasn't. Maybe it was related to things like your cognitive activity. Maybe you were using your devices too late at night.
I think it's really important actually for everybody to restrict their device use around the sleep period. As a rule of thumb, you might turn off your devices an hour before bed and not use them until, at least 15 minutes after you wake up in the morning. Certainly if you wake up at night even for extended periods, you shouldn't turn on your laptop or your phone.
[0:30:23]
Christopher: I think you're actually spot on, apart from the alcohol bit which you already pointed out was probably not the case. Absolutely, every single one of the things that you talked about, I know now to be true, including the cortisol awakening response. It just wasn't there. I didn't have one. So, yeah, absolutely, it was that kind of a multifactorial approach to solving the problem.
I agree actually about the hypoglycemia thing as well. If I've been wearing a continuous glucose monitor, I don't think I would have ever documented hypoglycemia during the night. It may have dropped down to 90 or something but nothing so low as to elicit a sympathetic response with adrenalin and cortisol and all that kind of stuff, I don't think.
Greg: Yeah, or if there was a response, it might have been entirely unrelated to the hypoglycemia.
Christopher: Yeah, absolutely. Let's talk about beds then. People love to talk about external stuff. It must be anything I'm doing. It must be my bed. There must be some sort of smoking gun and/or silver bullet here that I could use to solve this insomnia problem. So let's talk about furniture. I'm being mean because the bed does play a role. Correct?
Greg: Yeah, it does. It plays an underappreciated role, not in insomnia in general, but just if you think about small sleep problems that people experience. There could be a little bit of discomfort in bed that interferes with your sleep. Maybe you get too hot at night, for instance, or maybe you get too cold. If you adjust your bedding then you can probably help overcome those issues.
If you touch on the different factors to consider when buying a mattress first, there are probably three things that really come to mind. Those are comfort, durability and support. In general, people get what they pay for when it comes to mattresses. If you think about the fact that you spend about a third of your life asleep, current estimates are that you probably spend something like 30 to 60% of your time asleep, then you really should be happy to spend your money in getting a really good quality mattress.
With that said, what has happened in recent years is that these bed in a box mattresses have boomed in popularity. In order to be easy to transport around, they need to be foldable. What they're made of, of course, needs to be conducive to that, so they're made of foam. The problem with that is that foam tends to absorb heat. If you get too hot, of course, then you're not going to sleep well. Your body temperature should drop to about 36.2 degrees Celsius at night during the sleep period, at its lowest.
With that said, these manufacturers tried to use cooling gels to overcome that issue, but we don't really know how long the gels last. What this all means is that the good old fashioned spring mattress is probably a better option for most people because they dissipate heat more efficiently.
With that said, I know that many of the listeners are particularly interested in optimizing everything, and maybe they've tried some of these new technologies such as the chiliPAD. That company has a new device as well, which I think is called the OOLER. These are mattress toppers that you can use to regulate temperature of your mattress.
Christopher: I've got one. Yeah, I've got the old one. They were blowing them out. I was like, why is the sale price so spectacular, because I bought one. Of course they brought out the new one. I was like, oh, yeah, of course, I should have known that.
Greg: They're actually sending me one which I'm looking forward to try.
Christopher: Oh, it is super good especially if you sleep with someone that -- my wife wants to wear a bunch of clothes and pull tons of -- she's super hot, and she doesn't feel it. She's just radiating heat like crazy. So if you've got two people with different temperature requirements, you can set the two sides of the bed at different temperatures as long as you buy two different units. Yeah, it's super good.
Greg: I think that makes a lot of sense. On the subject of two people with different needs, if you think about mattress firmness too, let's say in a relationship you have one man who is 220 pounds and you have a girl who is 120 pounds. The man is probably going to need a foam mattress to be comfortable. You can get beds that have different firmness on either side, and that's a really important consideration for some couples. So if you can afford that and you think it's necessary then definitely look into those beds too.
The final thing I'll mention is that there are some smart beds now that basically try and assess how well you're sleeping and then optimize in-bed conditions according to their measurements of you. Some of those conditions will be things like temperature, but also the systems can link up with things like sunrise alarm clocks. Maybe you want to get up at a certain time. They can use that to gently wake you up from your sleep.
[0:35:20]
Or smart lighting systems, so if you are a very late chronotype and you want to go to bed very late but you want to also start shifting your sleep earlier over time so that you don't have to wake up to an alarm in the morning then these smart beds can tell your smart light systems to start to change your light environment in anticipation of bedtime to try and help you shift your sleep earlier.
Also, there's a bed named the BRYTE Bed, which I think has some motion functionality built into. I mentioned this to you in passing before, Chris. If you rocked somebody slowly about once every four seconds while they're in bed then they will actually fall asleep fast, and they'll sleep more efficiently. Also they'll tend to have more of these sleep spindles which are brainwaves that are particularly important to formation of declarative memories or memories of facts.
I think the BRYTE Bed system might also move you gently during your sleep if that's something that it deems is beneficial to your sleep. It's going to be really interesting to see how --
Christopher: Especially using machine learning to figure out what gets the best sleep, is that correct?
Greg: That's exactly what it's doing, yeah.
Christopher: That is cool.
Greg: It's tuning its parameters over time in response to changes in your own sleep which makes a lot of sense. Right now, there aren't published data on the bed, to my knowledge, so we'll have to see how it performs --
Christopher: Sorry to interrupt but this is what I've been talking a lot with Josh Turknett recently. It's like you're relying on the randomized controlled trial as the only means to acquire knowledge when you've just told me that supervised machine learning can do this much better for you as an individual at this time. Why would I rely on some stupid randomized controlled trial that was paid for by some mattress manufacturer on the other side of the world for people that were not my size, not my demographic, living somewhere else with a different latitude rather than just having a supervised machine learning algorithm figure out what's best for me tonight?
Greg: Yeah, and there is a move away from traditional RTTs in the literature, for sure. Certainly when it comes to analysis of N of 1 situations, whether that single unit is one person or one hospital, then alternative methods might be more appropriate.
I sent you a paper that Eric Hekler, who is at UCSD, published recently on this need for small data paradigm. In recent years, everybody has been about big data, but actually we can do an awful lot to help individuals in a much more rapid, more agile way by using some alternative methods. All sorts of different methods are available out there to the end. That's a long way of saying that I do completely agree with your sentiment.
Another thing to consider is that all of these manufacturers are forever updating their hardware and their firmware. With that in mind, let's say that a validation trial comes out of a particular device, by the time that publication is out in the real world, it's probably already out of date. They've probably already changed several things, and therefore we can't make inferences about the validity of that particular device based on that study. So, that all makes sense to me.
Just to circle back to the bed, I spoke exclusively about mattresses. Obviously it's important to have a comfortable duvet and pillows too. I'm not sure if the terminology is the same in the US, so I apologize if it's not, but…
Christopher: I think it is. I think my wife knows what I'm -- I still call it a duvet, and she knows what I'm talking about. They might say quilt. I'm not sure.
So, let's say this idea that the rocking motion is good and perhaps this harks back to our arboreal past. What do you think about the idea of hammocks then? A lot of people have been talking about hammocks on the forum.
Greg: I think they can probably be okay for lots of people. As you touched on there, we once would have slept in trees if you go back to a common ancestor that we share with a bunch of nonhuman primates. Then we came down from trees. Interestingly if we compare humans to other nonhuman primates then we actually have the shortest sleep of the primates, but we have the greatest proportion of sleep spent in rapid eye movement sleep specifically which seems to be particularly important to things like creativity and language and perhaps intelligence in general. Maybe that's one of the things that has permitted us to develop our complex social structures and things like language skills and tool-making and so on.
[0:40:05]
Anyway, if we've had too much REM sleep when we were in the trees, because during random sleep, our muscles, our skeletal muscles not our respiratory muscles, our heart obviously temporarily become paralyzed, then if the wind blew and our muscles are paralyzed then we would have fallen out the tree. That wouldn't have been much good. So, when we came down from trees, we could then have more REM sleep. With that said, the idea that rocking can positively affect sleep probably is related to this vestige from our time spent in trees.
To go back to the hammock now, is that a good idea? I think it depends on the person and I think in particular depends on their musculoskeletal system. Look at the problems of back pain worldwide. It's very common. It's enormously debilitating too. If you look at data on disability-adjusted life years or years of life lost due to disability then it's a massive problem. It's enormously burdensome compared to pretty much everything else out that's there. Different postures will exacerbate different types of back pain.
If you have a flexion-intolerant spine, you find tying your shoelaces aggravates your pain then sleeping in a hammock is going to be a really bad idea. If you have an extension-intolerant spine, let's say that you're lying down on the ground with your face down and then you look up at the wall in front of you by extending your spine or trying to extend your spine and that flares your pain then sleeping in a hammock might not be such a bad thing for you.
So I think it really depends on the person. I know for me, for example, for somebody who has had some back pain previously which is flared by flexion, sleeping in a hammock would be no good whatsoever, but others might find it really comfortable. If they live in a temperate climate where the air temperature is relatively ideal in the evening then it's definitely an option that you can consider.
Also there are other factors too, like exposure to light and noises. If you're in a hammock outside and you don't live in the middle of nowhere then you're probably more likely to be disturbed by something now.
Interestingly, I think there's a tendency for people to assume that recapitulating the pre-Industrial world is going to be categorically good for health, regardless. I think that we can sleep better in our modern sleeping environments than we could if we were sleeping outside given our ability to regulate things like temperature and to drown out noises and so on. So I think the opportunity is there.
Christopher: I'm such an asshole, and I apologize, because I realized that almost nobody is going to be able to reproduce this environment. What has been working really well for me at the moment is an idea that I stole from Rich Roll. Tommy and I went down to do a podcast with The Minimalists recently. I wasn't in the podcast. I was just like a weird audience of one. Rich Roll and Paul Saladino were there.
Rich Roll started talking about how he has been getting really good results sleeping in the garden, camping, so often sleeping in the bedroom with his wife. He would sleep in a tent in the garden. I thought, shit, that sounds great. So I tried it, only not in a tent. I've got this VW camper van I'm standing in front of at the moment. It has this pop top thing. There's a soft foam mattress which is very thin and then I put a very thin inflatable mattress on top of that. You don't pump it up. It's like one of those ones where you just get a bagful of air and squeeze the bag. It's really thin.
It was the most incredible night of sleep, and I swear that one of the reasons why is because it has got this 360-degree air space around you. It's like a mosquito net, but the winds can just flow right through it. I do live in a temperate climate. At the moment, it's getting up to like 36, 37 degrees C during the day but then it will drop right off to 12 overnight. So, that temperature shift is just amazing. I've been sleeping so well. I don't know. Is that useful? Can anyone else learn something from that? Is it likely to be applicable to a wider audience?
Greg: I'm just thinking about how many people who are in relationships are happy to leave their other halves and sleep in the van. It might just be of interest.
Christopher: I have to say that, first of all, it's not good for your sex life but then having small children is not good for your sex life anyway. My wife is quite happy for me to leave. She's in bed, a double bed with our 18-month-old son who's still not night weaned. Ivy breastfed until she was four years old. It looks like Beebo is going the same way.
He's still waking up during the night to feed. He only really wants to -- this makes total sense. Everything makes sense when you look at it through the lens of evolution. He wants to sleep touching his mother. He will only sleep through the night if he's physically touching her and when he wakes up, he wants to breastfeed.
[0:45:00]
Why does that make sense? Of course it makes sense. If you were a baby and you were that vulnerable, of course you'd want to be touching another human. That makes perfect -- what do we do? We put them in cots and cradles and baby monitors. All that stuff is completely bonkers. Anyway, my point is that my wife is quite happy for me to leave this situation and sleep in the van. So, it maybe works for everyone.
Greg: There could be something to it. All the article on it at the moment are those camping experiments which I touched on earlier. It seemed like people slept very well in those circumstances. Certainly if the temperature drops too low then that's likely to induce an arousal. If you look at guidelines about bedroom temperature recommendations, the suggestion in general is a temperature of about 18 Celsius is about right for most people.
Is a change in the temperature overnight better? For example, should the temperature wane slightly in accordance with the natural light-dark cycle? I don't know. I also don't know if that has been studied. I haven't actually looked for that research. It's an interesting research question. It's certainly one that could be answered. Intuitively it does make some sense, but I think most people aren't going to sleep in their camper vans. It might just be you and Rich, Chris.
With that in mind, it really comes down to people optimizing their bedroom temperatures. To go back to that, sometimes it's going to be a case of just changing your duvet if your duvet leaves you too hot in the middle of the evening.
Sometimes people might benefit from doing what I do in the summer which is I'll have my duvet with me but then I'll also have just the duvet cover without the duvet inside it. Quite often I'll wake up and I'll be a little bit too warm. I'll just roll down my duvet so that it's just around my lower legs, for instance, then I'll just use the duvet cover for the rest of my body. That completely removes any temperature regulation issue.
Even without going to that length, doing things like keeping your window open will be enough for some people. Or if you have air conditioning then that's probably going to be useful. If you don't have air conditioning then just using a fan and aiming at your torso might do the trick quite nicely. Those are a few different things to play with.
As you suggest, it might well be that a change in temperature over the course of the evening is ideal. With that said, it will be really interesting if the people at companies like BRYTE ever publish some of their data related to what ends up being optimal for many people. Obviously it's going to depend largely on an individual. Maybe they find over time that a change in bed temperature over the course of the evening seems to help consolidate people's sleep. That will be fascinating to know.
Christopher: Yeah, absolutely. I don't think having the data published is not going to be that helpful. What will be helpful is for them to publish a set of pre-trains parameters. These machine learning algorithms are going to be learning the ideal parameters for sleep and then you can just apply what you might call transfer learning. I can just download your parameters that you took five years to learn. I actually doubt that it will take that long to learn the parameters but, yeah, just transfer what works really well to my bed and then just run that as a program. Maybe that includes the sleep restriction therapy and everything else that you talked about. That would all be programmed into it so that you could just get back on track by following a program.
I could obviously keep you talking all day, and I want to be respectful of your time but not really because I'm going to ask you one more question. That is talk more about the skin temperature thing. I think a bunch of people on the forum have noticed this, that the hot-cold trick works really well. My experience has been it doesn't matter what it is you use to warm up before you cool down. A shower works. The sauna works. At the moment my favorite thing is the wood-fired hot tub so I'll get really warm. Even though, like I said, it has been 38 degrees C during the day, it cools off so rapidly at night. I'll warm myself up about half past 7, 8:00 at night, so I'm really quite hot. I can get out the hot tub and I'll have quite rapid cooling. Then I get to this point --
For some reason, I think this of you as well, Greg, is that you're one of these people that when sleep happens to you, when you get sleepy, you literally crawl across the bedroom and only just make it into bed before you fall asleep. That's exactly how I feel. I actually start to feel kind of ill. I'm so sleepy and as soon as I hit the pillow, I am out. It doesn't really say that I'm going to sleep all way throughout the night quite perfectly, but the sleep onset thing is totally solved by that hot-cold trick. Is that something I've learned about my own weirdness again? Tell me what you know about fluctuating temperature and sleep.
[0:50:05]
Greg: Yeah, it does seem to be useful specifically for helping people fall asleep faster. There's actually a meta-analysis that was published on this recently. When they collated the results of all the different studies that looked at pre-bed skin temperature raising activities such as having a shower or having a sauna, what they found is that they do tend to show that people will fall asleep faster if they go through these activities about an hour before sleep. You probably want to do these activities for ten to 20 minutes, something like that. The recommendation I normally give is to shower at 40 degrees Celsius for ten minutes about an hour before bed.
Certainly things like saunas might be useful too. I don't think there has been quite as much research on saunas specifically. Something to consider is that they might raise your temperature a little bit higher. If you're in there for a long period of time then they might raise your core temperature substantially too. You might therefore need a little bit more time before going to bed to cool off. The longer the duration of the exposure and the greater the intensity of the exposure, the further from bedtime you should probably engage in that activity.
Christopher: That makes sense. That has been my experience. If ever I do it, especially in the sauna, yeah, I'll be lying there in bed, just sweating. That's not what you want either.
Greg: Yeah. You want to raise the temperature of your skin by a couple of degrees, and that will draw blood out from your core towards your periphery. If you look at your hands and your feet, for instance, they have a very big surface area, but they have quite a small mass. They're very good at transferring heat of the environment. They can both gain and lose heat quite quickly through them. So if you warm your hands and feet in particular, but you can just warm your whole body by getting in the shower, then you can start to pull heat out of your core. That change in the proximal to distal temperature gradient is what's necessary to helping people fall asleep.
Interestingly, if you look at people who have insomnia, that temperature gradient doesn't seem to be quite so large, so temperature dysregulation is probably one of the things that interferes with their sleep too. Just to make it practical for people, ten-minute shower, 40 degrees Celsius, an hour before bedtime. Sauna, if you want to try one of those and been there for slightly longer, maybe keep it a couple of hours before bed. Both those things are likely to help.
Afterwards, you actually probably want to keep your socks on. I always say that. It always sounds silly, but heated socks do help people fall asleep faster. If you restrict their sleep period then they also tend to make sleep slightly more efficient such that the proportion of time people are spending in bed, a greater proportion of that time is spent asleep, so, probably socks on afterwards too.
Christopher: Interesting, I've not heard that one before. That's amazing. Well, Greg, with these series of articles, I feel like I've got at least two more podcasts in you. Maybe we should record those on another day. I don't know how you feel about coming back.
Greg: I'm very happy to. I feel like we haven't done sleep restriction therapy justice. Also, one of them is about sleep in athletes specifically, and there are a variety of different issues that they face which are somewhat unique to that population. It's probably worth touching on those, bearing in mind that some of your listeners like to test the limits of their physical capacities.
Christopher: Yes, absolutely. We know that sleep is perhaps one of the most important predictors of performance. Yeah, let's just hold this thought for now and then I'll get you back on the podcast. Just before you go, tell us where can people find you on the Internet? Maybe this is a good time to ask you about how you've changed your social media behavior over the last few months.
Greg: Which is in part thanks to you.
Christopher: It's not me, is it? It's Cal Newport.
Greg: No. It is Cal Newport. I used to read Cal Newport's blog periodically but then when you interviewed Cal, that was the final nudge that I needed to actually give the digital declutter a try. I haven't actually been that good at sticking to it very strictly. So rather than going through the 30-day period as he suggests and doing that in a [0:54:32] [Indiscernible] way, I tried to do that and then after about two weeks, I just found myself lapsing occasionally. I started again and that cycle repeated itself.
What has happened a couple of months later is that in general I'm just spending much less time on social media. Now I'll log into Instagram to share something that I contributed to, for example, or to share a discount or something, whatever it might be. I'll use self-control on my laptop to restrict my access to websites that I could otherwise waste time on. I've also started recording the number of minutes that I spend in deep work each day and tallying those.
[0:55:20]
I won't spoil the content of the podcast. I'll just say that people who haven't listened to it, people should go back and listen to your episode with Cal. It was excellent. They should probably read his books too, which I still haven't read. I will get to them at some point.
Christopher: That's amazing. You've gotten all of these out without actually reading -- that always blows my mind. Sometimes I meet people and they say, "Oh, I had a bunch of gut problems," or, "I had trouble sleeping. I listened to a couple of your podcasts, and it totally worked. Thanks very much." One guy came up to me the start of a bike race and said, "Oh, I had all these gut issues, and I tried that diet you talked about. What was it again?" AIP. "Yeah, that's it. Yeah, it worked perfect for me. Thanks very much." Fifteen seconds later, the gun went off, and I never saw him again. That's absolutely amazing. You put this stuff out there. You have no idea whether it's helping someone. That's incredible. You didn't actually read Cal's book, but you still got results just from listening to --
Greg: Yeah, absolutely. My screen time is way down on my iPhone, and I'm going for a walk each day without my phone on me. That's an enforced rule.
Christopher: Solitude.
Greg: Yeah, and I'm switching off all my screens at least half an hour before bed. People just won't get a response from me after 9 pm at the moment. I'm not turning them on during the night if I wake up or anything like that. So, all those small changes, I think have benefited me. Also, I do just the old more presence in general with people because I'm spending less time on things like social media. I also think that I'm more likely to reach out to friends just on a whim and say, "Are you kicking around this Thursday? I quite fancy catching up." So, it has benefited me in a few different ways.
Interestingly, apart from the last week or so, my sleep has been fantastic recently. It has been the best that it has been since I moved to London certainly. I think that some of that is a reflection on that digital declutter process. Obviously that's not something that I have empirical evidence for, but I can't imagine how it would hurt somebody's sleep. I could only see how it could help them with their sleep. So, go back and listen to that podcast if you haven't done so, read Cal's books, not that I have.
With that said, my social media is @gdmpotter on Twitter. On Instagram, I think my link in this is gdmpotter as well. You could reach out to me through any of those. You might not get an immediate response anymore, I'm afraid but, yeah.
Christopher: There won't be any Facebook Live or Instagram story, but you will -- I think that's what Cal is advocating. He's a professor of Computer Science, so it will be a bit weird if he was advocating for everybody to get rid of all their computers. Georgetown University will probably give him the sack if that was what he was advocating. He's just advocating for people to be more considered about their technology use and do their full cost-benefit analysis on everything that they do. That's hard because Facebook and other social media companies employ people called attention engineers who are using very specific tactics to stop you from being considered about your social media usage.
He's not saying there's no benefit. It's just that you should do the full craftsman approach which is what everybody has been saying on the podcast for the last five years. You listen to what Tommy has been saying about insulin resistance. He wants to do the full systems analysis. He doesn't want to just say, "Oh, well, white flour and sugar, that's the end of it." No.
Greg: It's all sugar.
Christopher: Malcolm Kendrick said the same thing. Cardiovascular disease is not just LDL. There's an entire process going on there that you need to understand. I really feel like that's the common thread there is all these people that want to do a full systems analysis and not just think in simple cause and effect.
Greg: Yeah, I think the other thing is just paying attention to your current patterns of behaviors, something that's enormously constructive to lots of people. In the attention economy, you're always being bombarded. What people need to train now is their capacity to discern useful things from things that just suck their time. It's especially important now because we have decentralized media and ensuring the quality of what you're exposed to is high, is quite hard.
The other thing is I think many of the people listening to this will probably listen to lots of different podcasts. Their podcasts just update automatically, and they'll just listen to whatever is near on top of the list. In the same way that if you search something on Google, you'll click on one of the first five hits. Actually, people should, in some instances, pause and then maybe start from scratch. Maybe you think, yeah, I actually never get anything from that particular podcast. Why am I listening to that?
When they go through that process and they start to think about what's important for them to expose themselves to then it both frees up their time and also they end up learning more efficiently too.
[1:00:10]
Christopher: Yeah, I think that's absolutely right. I would advocate for, if you're hosting a podcast and you listen to this, take some time to write meaningful titles for each episode of your podcast because that's what I'm using to decide whether I'm going to listen or not. There are a few podcasts that STEM-Talk is a good example where I'm just going to listen no matter what because they've done nothing but awesome things every single episode but not every podcast. In fact I think that's the only example I could think of where that's true. For everybody else, I'm using the title to decide whether I'm going to listen or not. If you put something like Episode 963 in the title of your podcast, that doesn't tell me anything about whether or not I should listen and so those characters are effectively wasted.
Greg: Yeah, well said.
Christopher: Excellent. Well this has been wonderful, Greg. I look forward to that next installment. Don't forget that Greg has written some really nice articles that I will link to in the show notes for this episode. Greg, thank you so much for your time. I very much appreciate you.
Greg: Thanks, Chris.
[1:01:07] End of Audio
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