Using Science to Optimize Sleep, Learning & Metabolism

**Andrew Huberman** (0:00)
Welcome to the Huberman Lab podcast, where we discuss science and science-based tools for everyday life.
I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost to consumer information about science and science-related tools to the general public. Along those lines, I want to thank the sponsors of today's podcast. Our first sponsor is Athletic Greens. Athletic Greens is an all-in-one vitamin mineral probiotic drink. I've been taking Athletic Greens since 2012, so I'm delighted that they're sponsoring the podcast. The reason I started taking Athletic Greens and the reason I still take Athletic Greens once or twice a day is that it helps me cover all of my basic nutritional needs. It makes up for any deficiencies that I might have. In addition, it has probiotics, which are vital for microbiome health. I've done a couple of episodes now on the so-called gut microbiome and the ways in which the microbiome interacts with your immune system, with your brain to regulate mood, and essentially with every biological system relevant to health throughout your brain and body. With Athletic Greens, I get the vitamins I need, the minerals I need and the probiotics to support my microbiome. If you'd like to try Athletic Greens, you can go to athleticgreens.com/huberman and claim a special offer. They'll give you five free travel packs plus a year's supply of vitamin D3 K2. There are a ton of data now showing that vitamin D3 is essential for various aspects of our brain and body health. Even if we're getting a lot of sunshine, many of us are still deficient in vitamin D3. And K2 is also important because it regulates things like cardiovascular function, calcium in the body and so on. Again, go to athleticgreens.com/huberman to claim the special offer of the five free travel packs and the year's supply of vitamin D3 K2. Today's episode is also brought to us by Element. Element is an electrolyte drink that has everything you need and nothing you don't. That means the exact ratios of electrolytes are an element and those are sodium, magnesium and potassium, but it has no sugar. I've talked many times before on this podcast about the key role of hydration and electrolytes for nerve cell function, neuron function, as well as the function of all the cells and all the tissues and organ systems of the body. If we have sodium, magnesium and potassium present in the proper ratios, all of those cells function properly and all our bodily systems can be optimized. If the electrolytes are not present and if hydration is low, we simply can't think as well as we would otherwise. Our mood is off, hormone systems go off, our ability to get into physical action, to engage in endurance and strength and all sorts of other things is diminished. So with element, you can make sure that you're staying on top of your hydration and that you're getting the proper ratios of electrolytes. If you'd like to try element, you can go to drink element, that's lmnt.com/huberman, and you'll get a free element sample pack with your purchase. They're all delicious. So again, if you want to try element, you can go to element, lmnt.com/huberman.
Today's episode is also brought to us by Thesis. Thesis makes what are called nootropics, which means smart drugs. Now, to be honest, I am not a fan of the term nootropics. I don't believe in smart drugs in the sense that I don't believe that there's any one substance or collection of substances that can make us smarter. I do believe, based on science, however, that there are particular neural circuits and brain functions that allow us to be more focused, more alert, access creativity, be more motivated, et cetera. That's just the way that the brain works, different neural circuits for different brain states. Thesis understands this. And as far as I know, they're the first nootropics company to create targeted nootropics for specific outcomes. I've been using Thesis for more than six months now, and I can confidently say that their nootropics have been a total game changer. My go-to formula is the Clarity formula, or sometimes I'll use their Energy formula before training. To get your own personalized nootropic starter kit, go online to takethesis.com/huberman. Take a three-minute quiz and Thesis will send you four different formulas to try in your first month. That's takethesis.com/huberman and use the code Huberman at checkout for 10% off your first order. Okay, let's get started. Today is episode three of the podcast and it is Office Hours. Office Hours, as many of you know, it's where students come to the office of the professor, sit down and ask questions, requesting clarification about things that were confusing or to simply go down the route of exploring a topic with more depth and detail. I asked for your questions to be listed in the comment section of the previous two episodes of the podcast on YouTube as well as on Instagram. And I, first of all, I just want to thank you for the many questions. They are excellent. We read them all. We distilled from that large batch of questions to two types of questions. Questions that were asked very often and were liked very often with the little thumbs up like tab, as well as questions that we thought could really expand on the topics that we've covered previously. And today we're going to cover both of those. If we did not get to your question, please don't despair. We will keep track of those. And we have several more episodes devoted to this topic of sleep and wakefulness and learning during the month of January, maybe even leaking over a little bit into the month of February. So we have time. That's one of the unique formats of this podcast is that we have time for dialogue. We have time for your questions. And we have time to really go deep into these topics. It's official Costello sleeping in the background. So if you hear snoring, Costello is going to be keeping time with his deep and melodic snoring. There he goes. So the questions that we received, I batched crudely into a couple of different categories, light, exercise, supplementation, temperature, learning, plasticity and mood and sort of mood related disorders. There were a lot of questions about those. Before we begin any of this, I want to point out something that I always say, it sounds like boilerplate, but it's important not just to protect me, but to protect you, which is that I am not a physician, I'm not a medical doctor, I don't prescribe anything, including behavioral protocols. I'm a professor, so I profess a lot of things based on quality peer-reviewed studies. You should take that information, you should filter it through whatever it is that you currently happen to be dealing with, whether or not that's health or illness, you should consult with a licensed healthcare professional before you add or remove anything from your daily life protocol. I'm not responsible for your health, you are, so be smart with this information and be a stringent filter, as we say. Okay, very well. Let's get started on the actual material. Somebody asked, what is the role of moonlight and fire? I'm presuming they mean fireplace or candle or things of that sort. In setting circadian rhythms, is it okay to view moonlight at night or will that wake me up? Will a fire in my fireplace or using candlelight be too much light? Great question. Also offers me the opportunity to share with you what I think is a quite beautiful definition of what light is in a quantitative sense. So I've mentioned a few times the use of apps and light meters and things to measure things like lux, which sometimes are also described in terms of candelas. So those are the two units for measuring light intensity. Typically lux, L-U-X is the unit. And so before we go forward and discuss this many lux or that many lux, I want to just tell you what a lux is because it relates to this question. One lux equals the illumination of one square meter surface at one meter away from a single candle. I bet that is. So somebody actually decided at some point that the amount of illumination at one square meter surface, one meter away from a single candle, that equals one lux. So when we talk about 6,000 lux of light intensity or 10,000 lux of light intensity, now you have a kind of a reference or a framework that would be the equivalent of, you could think of it as 6,000 candles all with their light intensity shown on one square meter from one meter's distance away. Or of course, if it was a different number of lux, it would be a different number of candles. So you get the idea. Here's the great thing. Turns out that moonlight, candlelight, and even a fireplace, if you have one of these roaring fires going in the fireplace, do not reset your circadian clock at night and trick your brain into thinking that it's morning. Even though if you've ever sat close to a fireplace or even a candle, that light seems very bright. And there are two reasons for that that are very important. The first one is that these neurons in your eye that I discussed in the previous episode, these melanopsin ganglion cells, also called intrinsically photosensitive ganglion cells, those cells adjust their sensitivity across the day. And those cells respond best to the blue-yellow contrast present in the rising and setting sun, so-called low solar angle sun, also discussed in the previous episode. But those cells adjust their sensitivity such that they will not activate the triggers in the brain that convey daytime signals when they view moonlight, even a full moon, a really bright moon or fire. Now, this does raise an interesting kind of thought point, which is, a lot of people have talked about lunacy and the fact that when there's a full moon out, people act differently and behave differently. There's a lot of lore around that. There's actually a little bit of quality science around that that maybe we can address in the future. But, moonlight is typically not going to wake us up too much, except maybe if the moon is really full and really bright, there's possibility for that. So, provided you're not going to burn down the structure you're in, you're not going to burn down the forest, enjoy your fireplaces, enjoy your lights from candles, and those are perfectly safe without disrupting your circadian rhythm, because we talked about just how crucial it is to avoid bright lights between the hours of about 10 p.m. and 4 a.m., except when you need to view things for sake of safety or work and so forth. I also received a lot of questions about red light. Now, I think I was asked those questions because red light is used in a number of different commercial products where these products tend to include a sheet of very bright red lights that one is supposed to view early in the day. And there are various claims attached to these red light devices that they improve mitochondrial function, that they improve metabolism. There, I'm going to be really honest and I can't name brands and I'm not going to name particular studies because what I'm about to say about these studies is not particularly unkind. But let's just say that none of the studies that I've seen, except for one that I'll talk about in a moment, pointing to the positive effects of red light on the visual system are published in blue ribbon journals. They tend to be published in journals that I had to work hard to find. I'm not sure what the peer review and stringency level is. Now that's not to say red light isn't beneficial because there is one study in particular that came from Glenn Jeffries Lab at the University of College London. It was published last year. Glenn is somebody I happen to know, he has an excellent reputation, excellent vision scientist. What this study essentially showed, and again, this is a study that I very much like the data and think it was done with very high standards. What this study shows is that viewing red light for a few minutes each morning can have positive effects on mitochondria in a particular retinal cell type that tends to degenerate or decline in function with age in humans. And that cell type is the photoreceptor. The photoreceptor is a type of cell in your eye that sits at the back of the eye. It's kind of some distance away from the ganglion cells. And it's the cell that converts light information into electrical signals that the rest of the retina and brain can understand. These are vitally important cells. Without them, people are blind. And many people's vision gets worse with age, in particular age-related macular degeneration, but also related to some other factors, including photoreceptor functionality, just getting worse with time. And what Glenn showed was that red light flashes delivered in particular early in the day, but not late in the day, can help repair the mitochondria. Now this study needs more support from additional studies, of course. They are doing a clinical trial. They did report on what I think it was 12 patients. And so the work is ongoing, but that was very interesting.