Essentials: The Science & Practice of Perfecting Your Sleep

Caffeine: Timing

The great science of sleep in the past five or 10 years has been, yes, quantity is important, but quality is just as important.

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NSDR can help offset some of the negative effects of slight sleep deprivation. And NSDR gets you better at falling back asleep should you wake up in the middle of the night. It's an extremely powerful tool that anyone can benefit from the first time and every time. If you'd like to try 8sleep, go to 8sleep.com slash Huberman to get up to $350 off the new Pod 5. 8sleep ships to many countries worldwide, including Mexico and the UAE. Again, that's eightsleep.com slash Huberman to save up to $350. So in this arc of the night, slow wave sleep predominates early in the night and then REM sleep. There's a scenario that many people, including myself experience on a regular basis, which is they go to sleep, sleeping just fine, three, four hours into it, they wake up. They wake up for whatever reason. Maybe there was a noise, maybe the temperature isn't right. We will certainly talk about sleep hygiene, et cetera. They get up, they go to the restroom. They might flip on the lights, they might not. They go back to sleep sleep let's say after about 10 15 minutes they're able to fall back asleep how detrimental is that wake up episode or or um event in terms of longevity learning etc it is perfectly natural and normal particularly as we progress with age at the end of our REM sleep period of the 90-minute cycle, almost everybody wakes up and we make a postural movement. We turn over because we've been paralyzed for so long and the body will also like to shift. For the most part, I think we can be more relaxed about that. Where we have to be a bit more attentive, though, is if you are spending long periods of time not being able to get back to sleep. And usually we define that by saying, if it's been 20, 25 minutes, the other thing is if it's happening very frequently. So even if you're not awake for 25 minute stretches, but you're finding yourself waking up and being consciously aware that you've woken up for maybe six, seven or eight times throughout the night. And your sleep is very what we call fragmented. The great science of sleep in the past five or 10 years has been, yes, quantity is important, but quality is just as important. And you can't have one without the other in terms of a good beneficial next day outcome you can't just get four hours of sleep but brilliant quality of sleep and be unimpaired nor can you get eight hours of sleep but have very poor quality of sleep and be unimpaired the next day. I'm a big proponent of people getting some sunlight, ideally sunlight, but other forms of bright light in their eyes early in the day and when they want to be awake. Essentially during the phase of their 24-hour circadian cycle when temperature is rising and then starting to get less light in their eyes as our temperature is going down later in the day and in the evening. I think that's exactly what we recommend right now, which is try to get at least 30 to 40 minutes of exposure to some kind of natural daylight. There was some great work recently coming out in the occupational health domain where they moved workers from offices that were just facing walls and, you know, didn't have any exposure to natural daylight. And then they did a time period during that study where they actually were in front of a window and working and they measured their sleep and their sleep time and their sleep efficiency increased quite dramatically. I think the increase in total sleep time was well over 30 minutes, and the improvement in sleep efficiency was 5% to 10%. And if you're batting an 80% sleep efficiency average, we're a bit concerned about that. But add 10% to that, now you're in a great echelon of healthy sleepers. These portals are the only way to convey to the rest of the brain and body about the time of day and wakefulness i have a number of questions about caffeine does the timing in which we ingest caffeine play an important role in whether or not it works for us or against us the dose and the timing makes the poison caffeine has a half-life and it's metabolized the half half-life is somewhere between five to six hours and the quarter life therefore is somewhere between 10 to 12 hours. It's variable. Different people have different durations of its action, but for the average adult, five to six hours. So let's say that, you know, I've been awake for 12 hours now and it's, you know, 8 p.m. And I'm feeling a bit tired, but I want to push through and I want to keep working for another couple of hours. So I have a cup of coffee. All of a sudden I was feeling tired, but I don't feel like I've been awake for 12 hours anymore. Then after a few hours and the caffeine is starting to come out of my system, not only am I hit with the same levels of adenosine that I had before I'd had the cup of coffee several hours ago, it's that plus all of the adenosine that's been building up during the time that the caffeine has been in my system. It's sort of an avalanche of... It is a tsunami wave, yeah. And that's the caffeine crash. Given somebody who typically gets into bed around 10, 1030 and falls asleep around 11, 1130. Yeah. When would you recommend they halt caffeine intake? And these are not strict prescriptives, but I think people do benefit from having some fairly clear guidelines of what might work for them. Would you say cut off caffeine by what time of the day? I would usually say, take your typical bedtime and count back 10 hours or eight hours of time. That's the time when you should really stop, you know, using caffeine is the suggestion. And the reason is because for those people who even just keep drinking up until, you know, into the evening, you're right that they can fall asleep fine. Maybe they stay asleep, but the depth of their deep sleep is not as deep anymore. And so there are two consequences. The first is that for me, and it can be up to by 30%. And for me to drop your deep sleep by 30%, I'd have to age you by between 10 to 12 years, or you can just do it every night to yourself with a couple of espressos. The second is that you then wake up the next morning and you think, well, I didn't have problems falling asleep and I didn't have problems staying asleep, but I don't feel particularly restored by my sleep. So now I'm reaching for three or four cups of coffee the next morning rather than just two or three cups of coffee. And so goes this dependency cycle that you then need your uppers to wake you up in the morning. And then sometimes people will use alcohol in the evening to bring them down because they're overly caffeinated. And alcohol, and we can speak about that too, also has very deleterious impacts on your sleep as well caffeine and alcohol represent the uh the kind of two opposite ends of the spectrum what happens when somebody has a glass we always hear a glass or two of wine in the evening or a uh a cocktail after dinner how does that impact their sleep so alcohol if we're thinking about classes of drugs, they're in a class of drugs that we call the sedatives. It's sedating your cortex. And sedation is not sleep. But when we have a couple of drinks in the evening, when we have a couple of nightcaps, we mistake sedation for sleep. Saying, well, I always, when I have a couple of whiskeys or a couple of cocktails it always helps me fall asleep faster in truth what's happening is that you're losing consciousness quicker but you're not necessarily falling naturalistically asleep any quicker so that's one of the first sort of things just to keep in mind the second thing with alcohol is that it fragments your sleep and we spoke about the quality of your sleep being just as important as the quantity. And alcohol through a variety of mechanisms, some of which are activation of that autonomic nervous system, that fight or flight branch of the nervous system. Alcohol will actually have you waking up many more times throughout the night. So your sleep is far less continuous. Now, some of those awakenings will be of conscious recollection the next day. You'll just remember waking up. Many of them won't be. And so, but yet your sleep will be littered with these sort of punctured awakenings throughout the night. And again, when you wake up the next morning, you don't feel restored by your sleep. The third part of alcohol in terms of an equation is that it's quite potent at blocking your REM sleep, your rapid eye movement sleep. And REM sleep is critical for a variety of cognitive functions, some aspects of learning and memory. It seems to be critical for aspects of emotional and mental health. It's overnight therapy. What we've discovered over the past 20 years here at the Sleep Center is that there is no major psychiatric disorder that we can find in which sleep is normal. And so I think that firstly told us there is a very intimate association between your emotional mental health and your sleep health. I don't want to be puritanical here. You know, I'm just a scientist and I'm not here to tell anyone how to live. All I'm trying to do is empower people with some of the scientific literature regarding sleep, and then you can make whatever informed choices that you want. My job is not to tell people a prescription for life. It's just to offer some scientific information. I would like to ask about marijuana in many places, not all medical marijuana is approved or is legal. Does marijuana disrupt sleep? THC can, seems to speed up the time with which you fall asleep. But again, if you look at the electrical brainwave signature of your falling asleep with and without that THC, it's not going to be an ideal fit. So you could argue it's non-natural. It too, but through different mechanisms, seems to block REM sleep. And that's why a lot of people when they're using will tell me, look, you definitely, I was dreaming. I don't remember many of my dreams. And then when they stop using THC, let's say I was having just crazy, crazy dreams. And the reason is because there is a rebound mechanism. REM sleep is very clever and alcohol is the same way in this sense. It's the same homeostatic mechanism. Some people will tell me, look, if I have a bit of a wild Friday night with some alcohol, you know, maybe I'll sleep late into the next morning and I'll just have these really intense dreams. So, and I thought I wasn't having any REM sleep. Well, the way it works is that it's during in the middle of the night, really, when alcohol blocks your REM sleep. And your brain is smart. It understands how much REM sleep you should have had, how much REM sleep you have not because the alcohol has been in the system. And finally, in those early morning hours when you're getting through to sort of 6, 7, 8 a.m., all of a sudden, your brain not only goes back to having the same amount of REM it would have had, it does that. Plus it tries to get back all of the REM sleep that it's lost. Does it get back all of the REM sleep? No, it doesn't. It never gets back all of the REM sleep, but it tries. And so you have these really intense periods of REM sleep. Hence you have really intense, bizarre dreams. And that's what happens also with THC. You build up this pressure for REM sleep, this debt for REM sleep. Will you ever pay it back? It doesn't seem as though you get back everything that you lost, but will you get back some of it? Yes. The brain will start to devour more because it's been starved of REM sleep for so long. I'd like to take a quick break and thank one of our sponsors, Roca. Roca makes eyeglasses and sunglasses that are the absolute highest quality. I've been wearing Roca readers and sunglasses for years now, and I absolutely love them. They're lightweight, they have superb optics, and they have lots of frames to choose from. Roca and I recently teamed up to create a new pair of red lens glasses. These red lens glasses are meant to be worn in the evening after the sun goes down. They filter out short wavelength light that comes from screens and from LED lights, which are the most common indoor lighting nowadays. I want to emphasize Roca red lens glasses are not traditional blue blockers. They do filter out blue light, but they filter out a lot more than just blue light. In fact, they filter out the full range of short wavelength light that suppresses the hormone melatonin. By the way, you want melatonin high in the evening and at night, makes it easy to fall and stay asleep. And those short wavelengths trigger increases in cortisol. Increases in cortisol are great in the early part of the day, but you do not want increases in cortisol in the evening and at night. These Roka Red Lens glasses ensure normal healthy increases in melatonin and that your cortisol levels stay low, which is again, what you want in the evening and at night. In doing so, these Roka Red Lens glasses really help you calm down and improve your transition to sleep. Roka Red Lens glasses also look great. They have a ton of different frames to select from, and you can wear them out to dinner or concerts, and you can still see things. I don't recommend you wear them while driving just for safety purposes, but if you're out to dinner, you're at a concert, you're at a friend's house, or you're just at home, pop those Roka Red Lens glasses on and you'll really notice the difference in terms of your levels of calm and all the sleep stuff I mentioned earlier. If you'd like to try Roka, go to roka.com, that's R-O-K-A.com and enter the code Huberman to save 20% off your first order again that's roca.com and enter the code huberman at checkout so i'd love to chat for a moment about the kind of grant the original i should say that not the granddaddy but the og of sleep supplementation which is melatonin yeah i was always taught and i'm assuming it's still true that the only source of melatonin in the brain and body is the pineal gland is that still true yeah it seems to be from best that we can tell i have to imagine we have melatonin receptors in the brain and body it's correct essentially your brain has a central master 24-hour clock called the suprachiasmatic nucleus that keeps internal time now it knows 24-hour clock called the suprachiasmatic nucleus that keeps internal time. Now, it knows 24-hour time, but it needs to tell the rest of the brain and the body the 24-hour time as well. And one of the ways that it does this is by communicating a chemical signal of 24-hour nuss of light and day using this hormone melatonin. And when it is at low levels or it's non-existent, it's communicating the message, it's daytime. And for us, dienol species, it says it's time to be awake. Yet at nighttime, when dusk approaches and the break comes off melatonin and we start to release it, then it signals to the rest of the brain and the body, look, it's dusk and it's nighttime. And for us, dienol species, it's time to think about sleep."

Melatonin: Benefits

It never gets back all of the REM sleep, but it tries. Hence you have really intense, bizarre dreams.

"so melatonin essentially tells the brain and the body when it's day and when it's night and with that when it's time to sleep when it's time to wake but it doesn't really help with the generation of..."

Caffeine: Adenosine

If you are going to nap, try to limit your naps, try to cut them off a bit like sort of caffeine, maybe, you know, eight to sort of not that far off.

"And the advice is if you can nap regularly and you don't struggle with sleep at night, then naps are just fine. But if you do struggle with sleep, stay away from naps."