Boost Your Energy & Immune System with Cortisol & Adrenaline

**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. In keeping with that theme, I'd like 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 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 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 Huberminute at checkout for 10% off your first order. Today, we're going to continue our discussion about hormones, and we're going to focus on how particular hormones influence our energy levels and our immune system. Now, last episode, I mentioned at the end that we were concluding our month on hormones, but we decide to include this additional episode. So this would be the fifth episode in the sequence of episodes about hormones, because there are two hormones, which are vitally important for a huge number of biological functions that we will talk about today, but that are particularly important for energy levels and your immune system. And this is something that I get asked about a lot. So rather than skip to the next general topic, today we're going to talk about the hormones cortisol and epinephrine, also called adrenaline. You do not have to have heard the previous episodes on hormones in order to understand and digest the material from today's podcast. If I mention anything related to previous episodes, I promise to give a little bit of quick background to get everyone up to speed. Today, we're going to talk about the biology of cortisol. We're going to talk about the biology of epinephrine. As always, we'll talk mechanism, and there are going to be a lot of tools. If you're somebody who struggles with stress and energy levels and balancing stress and energy levels, today's episode is going to be vital for you. If you're somebody who has challenges with sleep or you're somebody who has challenges getting your energy level up throughout the day and getting your energy level down when you want to sleep, today's episode is also for you. And we're going to talk about the immune system and how to enhance the function of your immune system. We're also going to get into some fun topics related to learning and memory and how you can leverage cortisol and epinephrine in particular in order to learn faster. We're going to talk about so-called nootropics, smart drugs and how they work because there's several of them that tap into the epinephrine system that aren't often discussed and that you have access to. We're going to talk about how caffeine can actually rewire your brain for better or for worse and we're going to talk about the biology of comfort foods and why they work so well and what they're doing and in understanding that you'll be able to better understand your food choices as they relate to short-term and long-term energy. So we have a lot to cover. Everything will be time stamped. I want to just remind people that we caption every episode in English and in Spanish. The captions take a day or two to pop up on YouTube. So if you're not seeing those within the first couple of days, please be patient with us in order to get captions that actually read similarly to what I'm saying. We go through a captioning service and so we have them done by experts and that takes a little bit of additional time. Meanwhile, if you have any questions as the episode evolves, please write them down. Please put them in the comment section. Please subscribe to the channel if you haven't already. And let's get started talking about how to increase your energy and improve and increase your immunity by leveraging the biology of cortisol and adrenaline. Before we dive into the biology of increasing energy and your immune system, I want to cover three topics that I promised I would mention from previous episodes. The first one relates to intermittent fasting. The second one relates to why your stomach grumbles. I forgot to mention the biology of that last time. And the third is a powerful way to increase growth hormone, which is powerful for increasing metabolism, fat burning and tissue repair, et cetera, that doesn't involve a sauna or wrapping yourself in plastic bags and going for a jog. So first, intermittent fasting. Last episode, I talked a lot about growth hormone and thyroid hormone. And I mentioned things like sauna and exercise and sleep and how they can increase levels of growth hormone within the healthy ranges. And why increasing growth hormone can be very beneficial because it can burn off body fat, it can improve muscle and general tissue health, cartilage, et cetera. And we tend to lose or our levels of growth hormone are reduced as we age. Many people asked me, well, what about fasting? Everyone's been promised on the internet that intermittent fasting leads to these big increases in growth hormone. The reason I didn't mention it is that I couldn't find a study that actually pointed to the underlying mechanism. I saw lots of claims, lots of podcasts, lots of degrees behind people's names, sometimes biologists, sometimes entirely different fields talking about this, but very few studies. And then I found what I would consider the study. We will link to this study. Turns out that fasting does increase growth hormone levels and the way that it does it is fascinating. I mentioned in a previous podcast about hunger and timing of meals and timing of hunger, that when you're hungry, you release a hormone in your body called ghrelin, sometimes actually called ghrelin. Thanks for all of you ghrelinistas or ghrelinistas that corrected my pronunciation. It's both, ghrelin or ghrelin, either one works. Ghrelin makes you hungry. When blood glucose, your blood sugar is low, ghrelin is secreted and makes you hungry. And it turns out that ghrelin, this hunger hormone actually binds to the receptor in the brain that normally binds what's called growth hormone releasing hormone. So believe it or not, the hunger hormone can act like growth hormone releasing hormone and thereby stimulate growth hormone. Now the levels of growth hormone that fasting promotes through this ghrelin system are pretty substantial. It's about a doubling of growth hormone levels in the waking state. So we know that you can release growth hormone in sleep, intermittent fasting, it turns out, can increase growth hormone by binding ghrelin to the growth hormone releasing hormone receptor. And it does it also during the daytime. So yes, indeed fasting can increase growth hormone, not to the supra levels that taking growth hormone would increase it or that a sauna could increase it, but it does seem to increase growth hormone. Later in today's episode, we're going to talk a lot about different patterns of fasting and eating that can control epinephrine. And so we will return to specifics about how long a fast. You need to fast for two or three days or 23 hours. Fortunately for people like me who love to eat, that's not the case. So we'll talk specific fasting protocols later in the episode. We also said we were going to talk about tummy grumble. When your stomach growls, it is not because of fluid sifting around in there. A lot of people think, oh, you know, it's fluid sifting around. Turns out that your stomach has smooth muscle that lines its sides. And when you eat something or you don't, every once in a while, your stomach cinches off at the two ends like a bag with a hose on either end, because that's essentially what your digestive system is. And if there's nothing in there, what happens is the muscles that line the sides of your stomach, they kind of extend around the stomach in these cables. Those are always there. And if you have food in your stomach, what they do is they churn your stomach. They literally turn the muscles of your stomach like a tumbler to help break up the food that presumably you didn't chew well enough because you were eating too fast. When you don't have any food in your stomach, that churning continues and that contraction of the muscle and the turning, literally turning over of your muscles, they don't flip over completely, but the turning over the muscles, that's what causes the stomach growling. If you don't want to be the person in the meeting or sitting there in a quiet theater whose stomach is growling, chew your food better. That's the simple solution. And last episode, I talked a lot about how sauna, controlled safe hyperthermia can cause huge increases in growth hormone release, anywhere from 300 to 500, even 1,600% increases in growth hormone release, really staggeringly high increases. I point out that many people don't have saunas in their yard or in their homes, and they would go through some other measures to increase safely their body heat, creating a steam room in their bathroom or jogging with extra sweats on, this kind of thing. Many of you asked about hot baths. Hot baths will increase growth hormones, excuse me. However, the temperatures that you need in order to increase growth hormone are high enough that you run the risk of burn. And so I really can't make any recommendations about hot baths, but if you can tolerate a nice hot bath, you are going to get some growth hormone release. However, the sauna has this advantage of you being able to enter a 175-degree or 200-degree environment, provided you're not pregnant, you're not a young child, et cetera. You can do that safely. And getting big increases in growth hormone, the hot bath will lead to lesser increases in growth hormone. We're going to talk a lot about temperature regulation in a future episode. But as always, if you're ever going to start playing with hypothermia or hypothermia, cold baths, ice baths, hot showers, hot baths that are beyond the kind of norm of what's comfortable, you have to be extremely careful and please consult a doctor. I think it's fair to say that most people would like to have a lot of energy during the day, if you work during the day, and they'd like their energy to taper off at night. And I think it's fair to say that most people don't enjoy being sick. Nobody wants to get sick. In other words, you want to have energy and you want your immune system to function well, to ward off infections of various kinds, bacterial infections, viral infections, et cetera. And it turns out that the two hormones that dominate those processes of having enough energy and having a healthy immune system are cortisol and epinephrine. Epinephrine is the same thing as adrenaline. In the body, we tend to call adrenaline adrenaline, and in the brain, we tend to call adrenaline epinephrine. And I'm sorry for that. I didn't create this naming system. And the story behind it is uninteresting and not worth our time. I will use the words adrenaline and epinephrine interchangeably today. Cortisol is cortisol. And I just want to cover a little bit about what cortisol and epinephrine are, where they are released in the body and brain. Because if you can understand that, you will understand better how to control them. First of all, cortisol is a steroid hormone, much like estrogen and testosterone, in that it is derived from cholesterol. Now that could be cholesterol that you eat. It could be cholesterol that's produced by the liver. As many of you probably know, the relationship between dietary cholesterol, the fats that you eat, and blood cholesterol and liver cholesterol is a very controversial one. It's a barbed wire topic. There are people that claim that dietary cholesterol has zero impact on circulating cholesterol coming from the liver. There are people who argue the exact opposite, both with good data in hand, I would say. There are some problems for the idea that all your cholesterol levels are determined by dietary intake, namely that anorexics often have very high levels of cholesterol that their liver produces, even though they are eating very little and sometimes not eating at all. So understand that cholesterol is a precursor molecule, meaning it's the substrate from which a lot of things like testosterone and estrogen are made. Please also understand that cholesterol can be made into estrogen or testosterone or cortisol, and that cortisol is sort of the competitive partner to estrogen and testosterone. What this means is no matter how much cholesterol you're eating or you produce, whether or not it's low or it's high, if you are stressed, more of that cholesterol is going to be devoted toward creating cortisol, which is indeed a stress hormone. However, the word stress shouldn't stress you out because you need cortisol. Cortisol is vital. You don't want your cortisol levels to be too low. It's very important for immune system function, for memory, for not getting depressed. You just don't want your cortisol levels to be too high and you don't want them to be elevated even to normal levels at the wrong time of day. So we're going to talk about how to control the timing and level of your cortisol.