Using Science to Optimize Sleep, Learning & Metabolism | Huberman Lab Podcast #3 Flashcards
How is light measured?
ne lux equals the illumination of one square meter surface at one meter away from a single candle.
How about red light?
So there’s a role for red light potentially early in the day and for mitochondrial repair in the photoreceptors, there’s a role for dim red light later in the day and at night. So you’re starting to notice a theme here which is that, there’s no immediate prescription of look at these light, it’s look at these lights potentially if that’s what you want to do at particular times of day and we’re particular intensities.
How about blue light and blocking this?
So these melanopsin retinal cells do react to blue light. That that is the best stimulus for one of these melanopsin cells, which led to the belief that blue blockers would be a good thing for preventing resetting of the circadian clock at night and deleterious effects of screens, et cetera. However, the people that made these products fail to actually read the papers from start to finish or if they did, they didn’t comprehend a critical element which is that most of those papers early on took those neurons out and put them in a dish. And when they did that, they divorced those neurons from their natural connections in the eye. It turns out in your IMI right now, because that’s what we care about, these cells exist and the cells respond to blue light but also to other wavelengths of light because they not only respond directly to light as they do in a dish, they also respond to input from photo receptors. Because people assume that blue light is the culprit because blue light is the best stimulus. That doesn’t mean that blue light is the only stimulus that will trigger these cells, okay?
How do seasons influence our ritme ?
And in general, it’s fair to say that in diurnal animals, meaning animals like us that tend to be awake during the daytime and not nocturnal animals, which tend to be awake at night. The longer the melatonin signal, the more depressed not necessarily clinically depressed, although that can happen but the more depressed our systems tend to be. Now this might lead you to say, “Well, then I should just really get as much light as I can all the time and reduce melatonin feel great all the time.” Unfortunately, doesn’t work that way because melatonin also has important effects on the immune system. It has important effects on transmitter systems in the brain, et cetera. So everybody needs to figure out for themselves how much light they need early in the day and how much light they need to avoid late in the day, in order to optimize their mood and metabolism.
Epinephrin vs adrenaline
Throughout this podcast and in previous episodes, I’ve been mentioning neuromodulators, things like serotonin and dopamine which tend to buy a certain brain circuits and things in our body to happen in certain brain circuits and things in our body not to happen. One of the ones I’ve mentioned numerous times is epinephrin which is a neuromodulator that tends to put us into action, make us want to move. In fact, when it’s released in high amounts in our brain and body, it can lead to what we call stress or the feeling of being stressed. Several people ask me, what’s the difference between epinephrin and adrenaline. Adrenaline is secreted from the adrenal glands which sit right above our kidneys. Epinephrin is the exact same molecule except that it’s released within the brain. And so people use these phrases or these words rather interchangeably, epi means near or on top of sometimes and neph, neph Anytime you see nephron or ph it means kidney. So it means near the kidney. So epinephrin actually means near the kidney. So it was used originally to describe adrenaline, but epinephrin and adrenaline are basically the same thing and they tend to stimulate agitation and the desire to move. That’s what that’s about.
When should I exercise?
And so I would never want these recommendations to seem like recommendations, what I’m really describing are some opportunities, 30 minutes after waking, three hours after waking or 11 hours after waking has been shown at least in some studies to optimize performance, reduce injury and that sort of thing. But you really have to figure out what works for you
Can I also use neural plasticity for big changes ?
So if you get onto a pattern or a rhythm, even if that rhythm isn’t down to the minute, you’ll find that there’s plasticity in these circuits and it becomes easier to wake up early. If that’s your thing or exercise at a particular day if that’s your thing.
Why do we sleep?
he meaning of dreams is a little bit controversial. Some people believe they have strong meaning other people believe that they can be just spontaneous firing of neurons that were active in the waking state and don’t have any meaning. There are good data to show that when you learn spatial, new spatial environments that there’s a replay of those environments, so-called place cells that fire in your brain only when you enter a particular environment, that those are replayed in sleep in almost direct fashion to the way that things were activated when you were learning that spatial task.
Can we accelerate learning with sleep?
here’s a study published in Cell Reports last year. Great journal, excellent paper showing that 20 minute naps or light sleep of a sort of non sleep deep rest taken immediately after or close to it, doesn’t have to be immediately after you finished the last sentence of learning or whatever it is, or bar of music. But you know, a couple of minutes after transitioning to a period of non sleep deep rest, where you’re turning off the analysis of duration path and outcome has been shown to accelerate learning to a significant degree. Both the amount of information and the retention of that information. So that’s pretty cool, because this is a cost-free, drug-free way of accelerating learning without having to get more sleep. But simply by introducing these 20 minute bouts. I would encourage people if they want to try this to consider the 20 minutes per every 90 minutes of ultradian learning cycle, there you’re incorporating a number of different neuroscience backed tools 90 minute cycles for focused learning. It could be motor, it could be cognitive, it could be musical, whatever, and then transitioned to a 20 minute non sleep deep rest protocol.
How is temperature related to the carcadian clock
AAnd that temperature has a very strong effect on things like metabolism and when you will feel most willing and interested in exercising, typically the willingness to exercise and engage in any kind of activity mental or physical is going to be when that rise in temperature is steepest. When the slope of that line is greatest. That’s why 30 minutes after waking is one of those key windows, as well as three hours after waking. And then when temperature actually peaks which is generally, generally about 11 hours after waking. So this is why we say that temperature and circadian rhythm are linked but they’re actually even more linked than that. We’ve talked before about how light enters the eye, triggers activation of these melanopsin cells, which then triggers activation of the super charismatic nucleus, the master circadian clock. And then I always say the master circadian clock informs all the cells and tissues of your body and puts them into a nice cohesive rhythm. But what I’ve never answered was how it actually puts them into that rhythm. And it does it two ways. One is it secretes a peptide. And peptide is just a little protein that floats through the bloodstream and signals to the cells. Okay, we’re tuning your clock. Kind of like a little, we know watch store, the watch store owner would tune the clocks. But the other way is it synchronizes the temperature under which those cells exist. So temperature is actually the effector of the circadian rhythm.
Temperature and carcadian clock
So for those of you that are having trouble getting up and this is going to almost sound laughable but a cold shower first thing in the morning will wake you up, but that’s waking you up in the short term because of a different mechanism which I’ll talk about in a moment, but it also is shifting your clock, it’s phase advancing your clock
in a way that makes you more likely to get up earlier the next day
Why cold showers?
But the goal of using cold exposure for stress inoculation and to raise your stress threshold to be able to tolerate heightened levels of real life stress, not the ice bath, but real life stress like work stress and relational stress, et cetera is by suppressing the activation of the so-called sympathetic nervous system, meaning the alertness or stress system. That involves buffering or trying to resist the shiver response. The shiver response is an autonomic response designed to generate heat, presumably, and actually that is what it does in order to counter the cold. So when you use cold exposure and you’re kind of muscling through it, or you’re learning to relax within it as a form of stress inoculation, that’s great and works quite well for that purpose. And I think that people assume that the ice bath or cold exposure is just one thing. Here I’ve talked about it three ways to shift your circadian rhythm depending on whether or not you’re doing it early in the day while your temperature is still rising or at its peak
or after that peak, in order to extend the perception of your day as continuing and make you want to go to sleep later and wake up later. Now, and then the third way of course is to either activate brown fat thermogenesis and increase metabolism. I suppose the fourth way would be to increase stress tolerance or stress threshold, okay?
What is the most important for the circadian rhythm
But I would love for people to understand that light
and temperature are the real heavy duty leavers when it comes to moving your circadian rhythm and sleep times and activity schedules and exercise and feeding can help, but really temperature and light, with light being the primary one are the most important
when it comes to sleep and wakefulness.
How does food influence the circadian rhythm
In all seriousness, low carbohydrate/fasted/ketogenic diets tend to lend themselves toward wakefulness by way of increasing epinephrin, norepinephrine, adrenaline dopamine, and things of that sort. Carbohydrate rich meals. And I suppose we talked about meals as opposed to diet tend to lend themselves more toward tryptophan, serotonin and more lethargic states.
How does food influence the circadian rhythm
In all seriousness, low carbohydrate/fasted/ketogenic diets tend to lend themselves toward wakefulness by way of increasing epinephrin, norepinephrine, adrenaline dopamine, and things of that sort. Carbohydrate rich meals. And I suppose we talked about meals as opposed to diet tend to lend themselves more toward tryptophan, serotonin and more lethargic states.
