How to get more quality sleep | (Science of Sleep Part 2)

The following is the transcript for the video by the same name on my channel “What I’ve Learned,” originally posted on February 10th, 2017.

I assume you’re here because you already understand that sleep is a top priority for good health. But in either case let me first quickly point out just one thing about sleep. Before you stay up late to get just little bit more work done, or to watch that movie newly added to netflix, think about the things you need to do or the decisions you need to make tomorrow, and decide whether all that is OK to do after a couple beers in the morning. 

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There are several studies that compare sleep impairment to drunkenness, and this one in particular found that just 17 to 19 hours of going without sleep ( a normal day for most of us..)“was equivalent or worse to a Blood Alcohol Concentration of 0.05 percent.”


In this talk Chris Barnes discusses how after 4 days on 5 hours of sleep, you’re almost the equivalent of too drunk to drive, and then in 14 days on 6 hours of sleep you are as bad as if you had stayed up an entire night.

Alright so how do we get more quality sleep?

We live in a very cyclic world. We have 4 seasons, stars have annual patterns, some birds migrate annually; and of course circadian rhythms are very important for most living things, even bacteria have circadian rhythms. Humans are no different. We have a daily dose of cortisol in the morning to wake us up and a rise in melatonin at night to put us to sleep at night. We also have ultradian rhythms- rhythms shorter 24 hours where we experience oscillations in alertness, concentration, and physical performance throughout the day.


Unfortunately nowadays we’re either moving so fast or medicating these rhythms with caffeine to the point that we’re no longer aware of them. However if you can act in sync with these rhythms, falling asleep and getting up in the morning can be as smooth and seamless as a rower hitting a good stroke. 

What we should strive for, and what our bodies would like for us to do, is to fall asleep just a few hours after the sun goes down. This differs depending on where in the world you are, but for most people it’s around 10PM. As Russell Foster explains in this talk, as you’re awake throughout the day, adenosine builds up in the brain and you develop a sleep pressure. Then during the night, physiological processes such as melatonin secretion work to set up a “sleep window”. If the buildup of sleep pressure and the sleep window are in alignment then you drift off to sleep without a hitch. However if the sleep window is out of sync with the sleep pressure due to using caffeine too much, having a wonky sleep schedule or because you’re stimulating yourself with your phone before bed, then you’ll miss your chance. After the sleep window closes, usually around 11PM your body is programmed to give you a second wind of energy in the form of cortisol which can keep you awake until as late as 2AM. 

Now, if you have the flexibility in your schedule to go to sleep at 2 and wake up at 9 that might not sound like such a big deal, but the anticarcinogen and antioxidant melatonin as well as Human Growth Hormone- the  “youth hormone” are secreted in their strongest doses between 10PM and 2AM. As Neurologist Kulreet Chaudhary says, “If your body is chronically deprived of the regenerative sleep between 10:00 p.m. and 2:00 a.m., then you may still feel fatigued when you wake up in the morning.” 

An easy way to set yourself up to fall asleep at this time is by resetting your biological clock by getting some sun in the morning between the hours of 6AM and 8AM. Research from the journal “Innovations in Clinical Neuroscience” found that exposure to sunlight in the morning significantly decreased cortisol levels later in the day. By getting some sunlight when you wake up, you set up cortisol and melatonin to be at optimal levels for getting a good night’s sleep and falling asleep at the right time. 

You will want to get this morning sunlight as often as possible. The human circadian rhythm is actually more like 24 hours and 10 minutes, so if you aren’t resetting it, then within a week you could end up on a sleep schedule that is an hour later than usual. 

A caveat here is that your body is very good at latching on to whatever rhythm it can, so if you for whatever reason your schedule does not allow for you to go to bed by 10PM, try and at least keep the same bedtime each night.

We’re a lot more like Pavlov’s dogs than we’d like to think. Your body will anchor whatever physiological processes it can to certain times of day and to your environment and even to objects. For example: While this baby’s association of water with sleep is cute, I’m sure no one wants to have to have water running on them to sleep. This is one reason why it’s imperative to keep the phone and laptop out of the bed. If you like watching movies or playing games at night, fine, but you don’t want your brain saying “Oh we’re in bed, it must be time to play flappy bird.” If you can train your mind to understand that 10PM is the time for sleep, and your bed is the place for sleep and only sleep, it will do the work for you. Then, if you can establish a pre-sleep routine that always happens in the same sequence- take a bath, make some herbal tea, read a book (whatever), that will create even more anchors associated with sleep and it will be even easier to pass out quickly after your head hits the pillow. 

Now this might not be all that compelling, but your brain really is good at automating processes like this.

Taking advantage of this automatic processing and establishing simple positive associations like “bed” only with “sleep” is called Cognitive Behavior Therapy and it’s used as a method for treating insomnia. Dr. Vyga Kaufmann explains in this talk that Cognitive Behavior therapy or CBTI is so powerful for treating insomnia that in the short run it is as good as medication and in the long run, “CBTI is the clear winner.” 

I said that you don’t want to associate the bed with using your phone, but there’s another big reason for this. The light and dark cycle perceived by the eye is  the most important regulator of your biological clock. You have something called Photosensitive Retinal Ganglion cells in your eyes that are highly sensitive to blue light in particular. Originally, the light from the sun was the only blue light that made it to our eyes, so having specialized cells in the eye to look for blue light was very effective for regulating our biological clocks. 

However, our technology has advanced dramatically, but our human hardware is still relying on these blue light sensors in our eyes to determine whether it is day or night and whether we should be alert or resting. When it comes to sleep, looking at a bright blue light is as alarming to your eyes as a loud barking dog is to your ears.

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As Shawn Stevenson explains in his book “Sleep Smarter,” “The artificial blue light emitted by electronic screens triggers your body to produce more daytime hormones (such as cortisol)” and suppresses the secretion of the key sleep hormone, melatonin. 

Researchers at Brigham and Women’s Hospital in Boston compared two groups, one reading on an iPad and another reading a printed book. Nighttime iPad readers secreted less melatonin, ended up taking longer to fall asleep, felt less sleepy at night, and had shorter REM sleep compared to those using printed books. What’s interesting is that they were also more tired than the book readers the next day, even if both got a full 8 hours of sleep.

iPhone、iPad、iPod touch で Night Shift を使う - Apple サポート

Try and stop looking at screens at least an hour before you go to bed so that your cortisol and melatonin levels can normalize. If you absolutely must get on the internet, make sure to at least get f.lux on your computer, and use the nightshift feature on your iPhone or get a blue light blocking app on your android. Blue light blocking glasses are great as well, but in any case, not looking at any bright screens is the best choice.  

You’ll also want to get your bedroom as dark as possible. There’s a light-sensitive chemical found in the retina called rhodopsin, which is also produced by the skin. If something is emitting light in your bedroom, it can interfere with your sleep even if your eyes don’t pick it up. 

Establishing a proper circadian rhythm is one of the best things you can do for your sleep as it will have you falling asleep faster and balances your hormones to give you higher quality sleep. 

As for enhancing sleep onset specifically, you can take advantage of the thermoregulation step of the sleep process. When it’s time to turn in for the night, there is a drop in your body’s core temperature to help initiate sleep. If your room is too hot, falling asleep can be a physiological challenge.  

    Studies have found that the optimal room temperature for sleep is around a cool 60 to 68 degrees fahrenheit. 

A study at the University of Pittsburg School of Medicine wanted to see if cooler temperatures could assist insomniacs with falling asleep. During the study, test subjects were fitted with “cooling caps” that contained circulating water at cool temperatures. What they found was that when the participants wore the cooling caps, they fell asleep even faster than people without sleep disorders. With the caps, the insomniacs took about 13 minutes to fall asleep, compared to 16 minutes for the healthy control group. The insomniacs also stayed asleep for 89 percent of the time they were in bed, which was the exact amount of time the healthy control group slept in bed. 

You can take advantage of this phenomenon by setting your thermostat lower of course, or you can take a cold shower or bath or take a warm bath. The relaxing nature of a warm bath is helpful and it doesn’t interfere with the thermoregulation step because your body starts to rapidly cool after stepping out of the bath, leaving you at a cooler temperature than you started with. Just make sure you get out of the bath at least a half hour before getting in the bed so you have time to cool off. A cold bath isn’t near as pleasant, but if you can handle it, it is really effective. I tried an ice bath twice recently and both times I fell asleep on the couch in my towel with the lights still on. 

Another thing I can say about sleep onset is to have the right expectations and try not to psych yourself out. As Psychology Professor Allison Harvey of Berkeley University says, you have to keep in mind that sleep is not a light switch but more like a dimmer switch. It takes most people on average about 20 minutes to fall asleep. Once you have the lights off, and you’re in bed there’s really not anything left for you to do so there’s no point in stressing out about how long it takes you to fall asleep. And actually it’s particularly  harmful for you to look at the clock. Clock watching is actually a well known exacerbator for insomnia. There’s even a phenomenon called placebo sleep where simply thinking you got more sleep the night before leads to better cognitive functioning. We can’t always trick ourselves into thinking we got good sleep but checking the time and saying “Shit it’s already 1AM!” is an easy way to make yourself anxious, secrete a little bit of cortisol and keep yourself up later. 

The best thing to do is to think about things unrelated to the consequences of everyday life, don’t review your embarassing moments, don’t think about your to-do list, while you’re laying in bed try and practice some form of meditation.

The other thing here is to improve the efficiency of the sleep process. Like we talked about last time, sleep is when your brain is shifting into waste cleanup mode. A specialized system called the glymphatic system floods the brain with cerebrospinal fluid and flushes out toxic waste products that have accumulated during the day. The cerebrospinal fluid (CSF) is produced by ependymal cells in the brain and in the central canal of the spinal cord. As well as CSF, the flow of blood to the brain increases during sleep.  1/5th of your circulatory blood goes to the brain to facilitate the sleep process. 

You want to make the process of routing your blood and CSF to the brain as smooth as possible. For this, the integrity of your spine is key. Going to bed with a stiff back or sleeping in the wrong position can be compromising your sleep quality. Since the spine is connected directly to every major organ in the body, your spine integrity can affect many other things like hormone production, muscular function, tissue repair, blood pressure as well as metabolism and digestion.

I was never too keen on Yoga until I tried a sequence before bed that is directed at loosening up the spine. The next morning I woke up about 45 minutes before my alarm clock feeling fresher than I had all week. The yoga may not have been the only factor, but taking a few minutes to loosen up my spine each night has generally improved my sleep recently. 

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Tim Ferriss recommends trying “gravity boots” or an inversion table to decompress the spine before bed. Doing a bit of stretching or yoga as well as rolling your back out on a foam roller is also very effective. 

The other thing you’ll want to do is make sure you’re in a decent sleeping position. The most common problem with people’s sleeping situation is that they are using too many pillows which hyperextends their neck, or they are sleeping on a worn out mattress which doesn’t support the natural curvature of the spine. 

As long as you’re not putting a kink in your back while you sleep, it seems that being on your back, stomach or side are generally fine. However, sleeping on the side is known to lessen sleep apnea by reducing snoring, and there is some compelling evidence that suggests sleeping on your side may be the best choice.

A 2007 study in The Journal of Allied Health Sciences and Practice, found that most people favored the side-sleeping position, and were less likely to wake up bothered by neck pain.

Then, Another study from 2015 in the Journal of Neuroscience looked at how sleeping positions affect the glymphatic pathway. Rodent models were used to see what sleeping position allows for the most efficient glymphatic transport, that is- how easily fluid could flow around so the brain could complete its cleanup job during sleep. Rodents slept on either their side, back or stomach and were monitored via magnetic resonance imaging. They found that glymphatic transport was the most efficient  when the rodents slept in the lateral position- on their side.

In the news release, Dr. Maiken Nedergaard said: “It is interesting that the lateral sleep position is already the most popular in humans and most animals — even in the wild — and it appears that we have adapted the lateral sleep position to most efficiently clear our brain of the metabolic waste products that built up while we are awake.”

There are some other very important factors that contribute to sleep quality like your body fat percentage or muscle mass, but for now these simple steps like changing your sleeping position or going to sleep a bit earlier and waking up earlier can have a profoundly positive impact on your sleep.

If you haven’t already, make sure and check out my last video which is all about why sleep is so important. If you’d like to improve your sleep, understanding what makes sleep so critical is the first factor in getting you to make the necessary changes.

*Two years later in July 2019, I made another video titled “What’s the Best Position to Sleep in? Do we even need a pillow?”

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