How to Prevent & Treat Colds & Flu

1. 0:00 – 1:58

   Avoid Colds & Flu

   1. AHAndrew Huberman0:00

      (instrumental music) 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. Today, we are discussing colds and flus. We will talk about what a cold really is and what a flu really is in terms of how they impact your brain and body. And of course, we will discuss how to avoid getting colds and flus. There are indeed some excellent science-supported techniques to avoid getting colds and flus. But of course, it is impossible to completely avoid ever getting a cold or flu in your lifetime. So we also discuss how to more quickly get over a cold or flu should you happen to catch one. So during today's discussion, I'll talk about the immune system. I'll give you some mechanistic understanding of how your immune system works, and I promise to make that discussion accessible to everybody regardless of whether or not you have a background in biology. And with that understanding of how your immune system works, you will be in a much better position to understand which tools, that is which protocols to implement, should you be exposed to a cold or flu or if you are trying to get over a cold or flu more quickly than you would otherwise. You'll learn about some potent behavioral tools for bolstering your immune system, and we will also discuss various compounds that you might consider taking to enhance the function of your immune system to ward off or treat colds and flus. I will also be dispelling a number of common myths about treatments for the common cold and for the flu. There are oh so many ideas out there about what one could take or do in order to avoid getting the cold or flu or more quickly get relief from a cold or flu. However, many of those are pure myth. There's just no science to support them. And indeed, there's some science that counters those ideas. But the good news is, there are indeed science-supported behavioral protocols and compounds that one could consider in order to avoid and treat colds and flus.

2. 1:58 – 6:00

   Sponsors: Joovv, Helix Sleep & ROKA

   1. AHAndrew Huberman1:58

      Before we begin, I'd like to emphasize that 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 Joovv. Joovv makes medical-grade red light therapy devices. Now, if there's one thing I've consistently emphasized on this podcast, it's the incredible role that light can have on our biology. And of course, I'm always telling people that they should get sunlight in their eyes as soon as possible after waking on as many days of their life as possible for sake of setting circadian rhythm, daytime mood, focus, and alertness, and improved sleep. Now, in addition to sunlight, red light and near-infrared light has been shown to have positive effects on improving numerous aspects of cellular and organ health, including faster muscle recovery; improved skin health and wound healing, even improvements in acne, or that is removal of acne; reducing pain and inflammation; improving mitochondrial function; and even improving vision itself. What sets Joovv apart and why it's my preferred red light therapy device is that it has clinically proven wavelengths, meaning it uses specific wavelengths of red light and near-infrared light in combination that trigger the optimal cellular adaptations. Personally, I use the handheld Joovv every day. The handheld Joovv is about the size of a thick piece of toast, and I also own a Joovv panel that allows for full body exposure, and I use that one approximately five times per week for about 10 to 15 minutes per session. If you'd like to try Joovv, you can go to Joovv, spelled J-O-O-V-V, .com/huberman. Again, that's joovv.com/huberman. For this month only, January 2024, Joovv is offering exclusive discounts to Huberman Lab listeners with up to $500 off select Joovv products. Again, that's Joovv, spelled J-O-O-V-V, .com/huberman to get up to $500 off select Joovv products. Today's episode is also brought to us by Helix Sleep. Helix Sleep makes mattresses and pillows that are tailored to your unique sleep needs. Now, sleep is the foundation of mental health, physical health, and performance. When we are sleeping well and enough, mental health, physical health, and performance all stand to be at their best. One of the key things to getting a great night's sleep is to make sure that your mattress is tailored to your unique sleep needs. Helix Sleep has a brief two-minute quiz that if you go to their website, you take that quiz and answer questions such as, do you tend to sleep on your back, your side, or your stomach? Do you tend to run hot or cold in the middle of the night? Maybe you don't know the answers to those questions, and that's fine. At the end of that two-minute quiz, they will match you to a mattress that's ideal for your sleep needs. I sleep on the Dusk, D-U-S-K, mattress, and when I started sleeping on a Dusk mattress about two years ago, my sleep immediately improved. So if you're interested in upgrading your mattress, go to helixsleep.com/huberman, take their two-minute sleep quiz, and they'll match you to a customized mattress for you. And you'll get up to $350 off any mattress order and two free pillows. Again, if interested, go to helixsleep.com/huberman for up to $350 off and two free pillows. Today's episode is also brought to us by ROKA. ROKA makes eyeglasses and sunglasses that are the absolute highest quality. I've spent a lifetime working on the biology of the visual system, and I can tell you that your visual system has to contend with an enormous number of challenges in order for you to be able to see clearly. ROKA understands those challenges and has designed their eyeglasses and sunglasses accordingly so that you always see with crystal clarity. ROKA eyeglasses and sunglasses are designed with a new technology called Float Fit, which allows them to fit perfectly and not move around even when you're active. In fact, whenever I'm wearing my ROKA eyeglasses or sunglasses, I usually forget that I'm wearing them. I happen to wear ROKA eyeglasses at night when I drive or if I'm reading at night, and I wear ROKA sunglasses during the daytime if it's very bright, especially if I'm driving into sunlight. If you'd like to try ROKA eyeglasses or sunglasses, you can go to roka.com, that's R-O-K-A .com, and enter the code Huberman for 20% off your first order. Again, that's R-O-K-A .com and enter the code Huberman at checkout.

3. 6:00 – 13:48

   Common Cold: Source & Transmission; Cold Temperature Myth

   1. AHAndrew Huberman6:00

      Okay, let's talk about the common cold. First off-No. Unfortunately, today, I cannot tell you the cure for the common cold because, indeed, there isn't one. One interesting question, however, is, why don't we have a cure for the common cold? And the reason is that the cold virus, as it's referred to, is actually a bunch of different viruses. Some colds are caused by one what's called serotype of the virus. Other colds are caused by a different serotype of the virus. There are over 160 different types of what people call the cold virus. Now, cold viruses fall under an umbrella of a general category of viruses called rhinoviruses. You can remember that easily because rhino sounds like rhino's horn or the rhinoceros horn, which is, (inhales) of course, in the center of the rhino's face, which is where your nose is, and the cold almost always causes some degree of nasal symptoms in humans. It's either runny nose or sneezing or stuffed up nose or sometimes, unfortunately, all three. Now, the reason we don't have a cure for the common cold is that all of those different serotypes of the cold virus mean that the virus itself has a different shape on its outside. And as a consequence, even if you've been exposed to a cold and you've developed antibodies against that cold virus, the next cold that comes along very likely has a different shape, and therefore, your body's antibodies to the cold virus it combated successfully before can't latch onto and defeat that next different serotype of the cold virus. Now, a little bit later, I'll talk about the immune system and how those different antibodies are generated. But for the time being, understanding that there are a lot of different types of cold viruses explains, first of all, why we don't have a cure for the common cold, but also why you can get multiple colds within a given year or even within a given season. Because even if you develop antibodies against one serotype of the cold virus, a different serotype can come along, and you can get sick again with that new serotype of the cold virus. So how do you catch a cold? Now, one of the problems with the cold virus being called the cold virus and the fact that, indeed, there are more cold viruses present and transmitted between humans in the cold winter months of the year is that people generally assume that it is the cold temperatures outside that actually give you a cold virus, and that is simply not true. However, what you heard as a kid, if your mom, most likely, but maybe your dad said, "Hey, don't go outside without a sweater or jacket on. You're going to catch a cold," or, "You're going to catch cold," you know, has propagated this, uh, this myth that the cold temperatures themselves are the cause of catching a cold virus, and that's simply not true. The virus that we call the cold virus is spread by breathing or by sneezing or by people sneezing or coughing or breathing onto their hands and then touching surfaces and then other people touching those surfaces and then touching most likely their eyes in order to self-infect. Now, we're going to get into the details of how far the virus can spread with a sneeze, how long it can survive on the hands, et cetera. But for the time being, know this. The cold virus is a pretty stable virus in that it can survive on surfaces, non-human or human surfaces, meaning skin or on a table or on a glass or on a door handle, for up to 24 hours. So for all you hypochondriacs out there, I probably just gave you a little spike in cortisol. And for you non-hypochondriarchs, I hope what I just said cues you to the fact that just avoiding people who are sneezing and coughing is not sufficient to avoid getting colds and flus. However, the fact that a cold virus is alive and well on a given surface, let's say on a door handle, does not mean that if you touch that door handle that you will necessarily be infected with that cold virus. And that's because your skin actually provides an excellent barrier against most viruses and bacteria. Your skin also includes a lot of antiviral substances on it, even if you haven't put any of that, you know, alcohol stuff or the hand sanitizer stuff on. Your skin is a very important barrier component of your immune system. We're going to talk about that a little bit later. But if somebody has a cold and they happen to perhaps, you know, wipe their nose or sneeze into a tissue, hopefully into a tissue and then discard that tissue, the cold virus particles are extremely small. How small? Well, most of us are familiar with thinking about centimeters or inches. If you think about a millimeter, being 1/100th of a centimeter, well, you can take a millimeter and you can divide that up into a bunch of little slices also such that you get the micron. The micron is 1/1000th of a centimeter. And if you want to get a sense of how thick or thin that is, the side of a credit card, the little thin side of a credit card, is about 200 microns thick. So if you set your credit card flat on a table and then you look at it from the side, that tiny, tiny thin little edge, that's about 200 microns. The cold virus is made up of particles that are probably in the range of about five microns or so, so it's extremely small. I mean, the cold virus, therefore, with a good sneeze or even a light sneeze, can spread really far. Now, the good news is those particles are relatively heavy. They don't tend to mist about in the air for very long. They tend to fall down onto the ground or onto surfaces. But as I mentioned before, they can survive for a very long time on those surfaces. So should you touch your hand to a door handle or table or shake the hand of somebody that has cold virus on their hands, either because they themselves have a cold or they contacted somebody else that had cold virus and it somehow landed on their hands just 'cause the other person sneezed, all these scenarios are very realistic, that cold virus will not infect you unless it can get inside of your body. And one of the primary entry points of it getting inside your body is via the eyes, by wiping that cold virus on your eyes. Now, you may think, "Okay, I'm just not gonna touch my eyes." But a little bit later, we're going to talk about a study that shows that almost always, indeed, almost always, when you meet somebody new, you touch your eyes. And the frequency of people touching their face-... that is the region of the face around the eyes, and their eyes, throughout the day is extremely high. So this is one of the primary routes by which the cold virus is transmitted from one person to the next. But of course, there's also the route that we're all familiar with, which is the person that is sneezing, or coughing, or blowing their nose into tissues, and then throwing them in the trash, and not washing their hands after each and every time they do that. So an important aspect of today's discussion that we will get into, once I also present to you what a flu is and how it differs from the cold, is that we're going to need to talk about what stage of infection people are actually contagious with the cold or flu. And there's actually a lot of mythology about this. In fact, there's a lot of just lying about this. People will be coughing or sneezing, and they'll say, "Oh, yeah, I'm not contagious any longer." Or people make up these things like, "Oh, you know, if you had the flu for two days, then you're no longer contagious," or that you can't be contagious until you have symptoms. So we're going to go through all the aspects of contagion and how coughing or sneezing, or how long you've had a cold or flu actually relates to whether or not you're contagious in a little bit. But for the time being, know that the cold virus is very, very small. It can be transmitted through the air, it can be transmitted via contact, from skin-to-skin contact, and it can survive on surfaces for up to 24 hours. And when you touch those surfaces or a person with the cold virus, most often the way it's going to get into your body and infect you such that you get a cold is by touching your eye region. Although touching other regions of your body can also pass the cold virus into you, for instance, the mouth and lips, but that's actually far less common. So we'll get into that in just a little bit. Now, different serotypes, that is different types of cold virus, tend to create a different

4. 13:48 – 17:43

   Spreading a Cold; Symptoms & Contagious Myths

   1. AHAndrew Huberman13:48

      array of overall symptoms, such that, you know, one cold might be a really, quote-unquote, "bad cold." Others are more mild. Some tend to induce more runny nose, others more stuffy head and a little bit of fever, or in some cases a lot of fever. One thing that's important to understand is that if people are going to be infected by the cold virus, they tend to develop symptoms one to two days after they were exposed to the virus. Now, the good news is, if you are exposed to the cold virus, that doesn't necessarily mean that you are going to catch that cold virus. That is, if your immune system can fight off that cold, even if you've never been exposed to that serotype before, then you won't actually have that cold and you won't transmit it. So put differently, it is possible to avoid getting a cold virus even if you've never been exposed to that serotype of cold virus and you happen to come into contact with somebody who has that serotype of cold virus, or you touch a surface of some object, door handle, et cetera, that has a particular serotype of the cold virus on it and God forbid you then wipe your eyes. That doesn't necessarily mean that you're going to get sick. And a good portion of today's episode is going to focus on tools that are supported by science that allow you to bolster your immune system and greatly increase the probability that even if you're exposed to a novel serotype of the cold virus, that is one that's new to you, that your body's never seen before, that you won't get sick. Another thing to understand about the cold virus is that you're generally most contagious to other people when you feel at your worst. That is, when you're coughing and sneezing and you got that stuffy head, watery eyes, and so on. But you can also be contagious to other people when you are starting to feel better. That said, most of the data point to the fact that about five to six days after you hit your peak of worst symptoms, or I guess we should say your nadir, the dip of worst symptoms 'cause it's such an awful state to be in, you are probably exiting the phase in which you're contagious. Now, I want to be very clear, that does not mean that if you've had a cold for five or six days that you are no longer contagious. If you continue to experience sneezing and coughing, watery eyes, in the evening you're feeling much worse, first thing in the morning you're feeling especially groggy, et cetera, well then you are still contagious. Another way to frame this is, you know those people that continue to show up at the gym and show up at work and they tell you, "Yeah, I got this cold, but I've had it for a few days, I'm no longer contagious." (imitates person coughing) And they're wiping their eyes and they're blowing their nose. Frankly, they don't know what they're talking about. They are basically a walking, talking, breathing, sneezing, coughing cold virus vector. A vector is a route for passage of a virus. So please, if you are sneezing, if you are coughing, if you are still experiencing the symptoms of a cold, stay home. Stay away from other people as much as possible. And I realize that some people simply cannot avoid going to work or cannot avoid interacting with other family members or other people if they have the cold virus, but this mythology that if we've had a cold for a few days and we're starting to feel better but we're still exhibiting symptoms, that we're not contagious, that is pure myth. It's simply not grounded in fact. Now, there's nothing that can be done about that first day or two after which we're exposed to a cold virus where we are not experiencing symptoms, and it's quite possible to pass the cold virus on to other people. But I think that every workplace, every home environment, every gym, every society would benefit greatly if people who were sick with the cold did not expose other people to that cold virus as much as possible. And indeed, this is a serious issue. It's not just about a few sniffles and watery eyes. There's an enormous financial and mental health cost and physical health cost to people getting the cold, and it's not just about people who are immune-compromised or elderly people. What we're generally referring to as the cold today can be mild, it can be moderate, it can also be very severe, and it can exacerbate other health issues that people have. And we'll talk about that a little bit later and how to offset some of those health issues. Okay,

5. 17:43 – 23:56

   Flu Virus & Transmission; Flu Shots

   1. AHAndrew Huberman17:43

      so now let's talk about the flu virus. The flu virus is, as I mentioned, a virus. And just like with the cold, there are different serotypes of the flu virus. There are also different general categories of flu virus. So you've got your A-type flu viruses, your B-type flu viruses, and your C-type flu viruses. And by the way, I'm saying flu viruses, but of course I'm referring to influenza, but it's just kind of commonplace nowadays to refer to influenza as the flu.Similar to cold viruses, the different types of flu viruses exist based on the different types of proteins that they express on their surface. In fact, in the news over the last few years, there have been a number of different flu virus strains that have been described according to their surface protein characteristics, things like the H1N1 virus. What is H1N1? H1N1 describes the different types of proteins that are expressed on the surface of that particular flu virus. Now, the most common type of flu viruses are in that A category of flus. This is the type of flu that caused the Spanish flu. Now, the Spanish flu, which, by the way, did not originate in Spain, people think it probably originated in New York or perhaps elsewhere, but certainly not in Spain, killed anywhere from 17 to 50 million people, depending on which literature you read. That's an enormous number of people, and it occurred in four different waves of infection that occurred between the years 1918 and 1920. The Spanish flu was a type A H1N1 virus, and actually, it's worth noting that this winter season, there have been some cases of H1N1 already reported in the United States and elsewhere. Now, of course, the goal is always to contain the propagation of those flu viruses, and that is done through a number of different approaches. The best and most reliable approach, of course, is to not come into contact with somebody that is carrying the H1N1 or any other type of flu virus. However, based on the way that the flu virus infects the body, the way that the symptoms emerge, and the ways that viruses propagate, that can't always be avoided. One thing to know, and I consider this a fortunate aspect of flu virus biology, is that the flu virus, unlike the cold virus, can only exist on surfaces for about two hours. After about two hours, it tends to die off. So the flu virus is most typically passed by human-human contact or coming into contact, that is walking into a cloud of somebody's sneeze that contains flu virus or somebody's cough that contains flu virus, and yes, it is possible that shaking someone's hand could actually introduce flu virus to your hand, and then if you wipe your eyes, or I'll talk about a few other portals of entry for the flu virus and cold virus in a few minutes, can get into your body and infect you. And yes, you can pick up the flu virus from surfaces. However, that is far less common than the flu virus passing from human-human contact. Now, there aren't as many different types of flu virus as there are types of cold virus, and that's why there have been attempts at making flu vaccines or so-called flu shots. I think most people are familiar with the signs and advertisements online and in the workplace and schools saying, you know, "Get your flu shot this season." The reason that flu shots can exist at all is because there are limited enough types of flu virus present in a given year that specific vaccines, that is flu shots, can be generated against that particular strain of the flu virus. So how effective is the flu shot? And I want to be very specific here. When we say the flu shot, singular, it sort of implies that there's one flu shot that can combat all the different types of flu, and as you just learned, that is not the case. So we probably should be saying the flu shots, but just for sake of simplicity, when I say the flu shot, I mean the flu shot that's given in a given flu season that is directed at specific strains of the flu, because researchers have determined that that particular strain of flu or strains of flu are the ones that are most abundant for that particular flu season. Studies have shown that getting the flu shot reduces one's risk of contracting the particular flu that is most abundant that season by about 40% to 60%. But of course, the flu shot is completely ineffective at combating any other forms of the flu virus and, of course, colds or other types of upper respiratory infections. Studies have also shown that taking the flu shot can reduce the severity of one's symptoms if they, in fact, get the flu anyway. Now, personally, I don't typically get the flu shot, and the reason for that is that I don't tend to go into environments where I am particularly susceptible to getting the flu. I don't work in a hospital or a clinic, I don't tend to interact with large numbers of people on a daily basis, so for me, I've opted not to get the flu shot. Now, that doesn't mean that I've never contracted the flu. As I mentioned earlier, I tend to get sick with a cold or flu about once every 18 to 24 months, and the severity of that cold or flu has ranged from, you know, at one point a very high fever in one case, but typically a moderate fever and the usual symptoms of malaise that we've been discussing, and I've managed to get over those without having taken the flu shot pretty easily. Now, of course, we also don't know that those were actually flus. Despite the distinct differences between the symptoms of cold and flu, most people don't really know whether or not they have a cold or flu. So this is another thing to think about when considering whether or not to get the flu shot. Ultimately, because at least to my knowledge, most workplaces do not mandate that people get the flu shot, I could be wrong about certain workplaces, but my experience is that most workplaces do not mandate that people get the flu shot, when you take the flu shot, you're really hedging a bet. You're hedging a bet against the fact that you will be or not be exposed to that particular strain of flu virus that's most abundant that season or strains of flu virus that are most abundant that season, and that the flu shot that you're taking is directed at those particular strains. So again, in my case, I don't tend to take the flu shot, but of course, you need to make the decision that's right for you. For instance, if you have family members that are immune-compromised or you work in a school or you think that you are exposed to a lot of flus or you're concerned about transmitting flu to any one individual or group of individuals, those are all things that need to be taken into consideration, and of course, speak to your physician.

6. 23:56 – 27:16

   Tools: Injections & Safety; Charting Health Trends & Sickness

   1. AHAndrew Huberman23:56

      I will also say this, which is that I mentioned that I've tended to catch colds or flus at a rate of about once every 18 to 24 months, and when I say a cold or flu, I mean a, a serious one, one that keeps me in bed where I have a fever and I'm sweating. What I have done and I continue to do is because I pay...... Pretty close attention to how well I'm sleeping, or different life events, my different workouts, et cetera, and I put those into my calendar. And I have a shorthand to do that, so it only takes about 30 seconds each day. Okay, did this work out? It was kind of level seven out of ten intensity. Got good sleep last night, or poor sleep, and I know what good and poor sleep is for me. I mean, that's about the level that I'm charting these things. I have been able to go back and look at the events preceding when I've come down with a cold or flu. Again, I don't know whether or not it was a cold or a flu, but before I got sick. And I have seen, for instance, like if I've ever done two hard workouts in a day, something I never do any longer, I've tended to get sick after that. If I've tended to do hard workouts and then expose myself to cold temperatures while traveling, especially traveling overseas, that tended to precede those colds or flus, which again, for me, are very seldom. So it's a limited data set. This is entirely anecdata, meaning related to my own history of getting colds or flus. But it's something that I actually recommend people do, which is, you know, to pay attention to when you first started getting symptoms, pay attention to when you got over a given, what you think is a cold or flu, and then to look at what was happening in the days before and that day. I don't think it's possible to do hyper precise forensics on a cold or flu, right? I mean, you could have gone into the gas station, put your credit card in the machine to, you know, grab a drink out of the refrigerator, and picked up a cold or flu from the handle of the refrigerator or from the credit card machine, or even from the gas pump. You simply don't know. However, if you look at the pattern of behavior, travel, sleep, exercise, sorts of interactions you were having prior to getting a bad cold or flu, chances are you're gonna learn something interesting and be able to avoid getting a serious cold or flu, at least to some extent, going forward. And I've done that, I think, fairly successfully because I can tell you that the frequency of colds or flus that I've come down with has indeed been dropping from year to year. So whereas a decade ago, I tended to get colds or flus probably about once a year, and in some cases even twice a year, although that was pretty rare, that really expanded to about once every 18 months. And then in the last five years, I think I've gotten sick, uh, two times pretty badly with a cold or flu, and then once with a kind of mild cold or flu. So I tell you all that just as an example of how you can start to think about how your immune system interacts with different types of behaviors, different types of situations, such that you can learn something about your immune system and what's going to best protect you against getting colds and flus going forward. Which of course, is a great thing to do because we all think that we can get out there, be around people that are coughing and sneezing, we can go to the gym when it's crowded in winter. Oh, that person over there is, you know, coughing, but I'm gonna just, you know, stay a few feet away, no big deal. And while I don't want to turn anyone into hypochondriacs, that's how you get infected, that's how you get a cold or flu. And at the same time, I don't think anyone should, you know, get to the point where they're afraid to go into a gym or afraid to go to the workplace. But I will say, once again, if you're sick with a cold or flu, if you are coughing, sneezing, blowing your nose, runny eyes, and you're walking into work or the gym or onto public transportation and you're telling people, "I'm not contagious," you're lying.

7. 27:16 – 28:44

   Sponsor: AG1

   1. AHAndrew Huberman27:16

      I'd like to take a brief moment and thank one of our sponsors, and that's AG1. AG1 is a vitamin mineral probiotic drink that also contains adaptogens. I started taking AG1 way back in 2012. The reason I started taking it and the reason I still take it every day is that it ensures that I meet all of my quotas for vitamins and minerals, and it ensures that I get enough prebiotic and probiotic to support gut health. Now, gut health is something that over the last 10 years we realized is not just important for the health of our gut, but also for our immune system and for the production of neurotransmitters and neuromodulators, things like dopamine and serotonin. In other words, gut health is critical for proper brain functioning. Now, of course, I strive to consume healthy whole foods for the majority of my nutritional intake every single day, but there are a number of things in AG1, including specific micronutrients that are hard to get from Whole Foods, or at least insufficient quantities. So AG1 allows me to get the vitamins and minerals that I need, probiotics, prebiotics, the adaptogens, and critical micronutrients. So anytime somebody asks me if they were to take just one supplement, what that supplement should be, I tell them AG1, because AG1 supports so many different systems within the body that are involved in mental health, physical health, and performance. To try AG1, go to drinkag1.com/huberman and you'll get a year's supply of vitamin D3K2 and five free travel packs of AG1. Again, that's drinkag1.com/huberman. Now, the

8. 28:44 – 30:43

   Spreading Cold & Flu, Symptoms

   1. AHAndrew Huberman28:44

      diabolical thing about the flu virus is that just like the diabolical thing about the cold virus, you start shedding virus, that is you are contagious about 24 hours prior to the onset of first symptoms for you. So that means that you can be a flu viral vector even when you aren't having symptoms. That's just the unfortunate aspect of these viruses. They're very clever, they don't have brains, but these viruses have adapted to propagate from host to host to host. They have a drive to continue to stay alive and to infect more hosts. So even though they don't have a brain, they have a sort of a, let's call it viral intelligence. And as I've said several times now, if you are still exhibiting symptoms of the cold or flu, you are contagious. However, with respect to the flu, you are most contagious during the three days when you feel the absolute worst, when your fever is at its worst. We'll talk about how to deal with fever a little bit later. When you are coughing and sneezing, headache, all of that, when that is at its peak, that is when you are most contagious. So again, I realize that people can't always avoid contact with other people. You know, you live under the same roof, sometimes caretakers interacting with the person that has the cold or flu. And I do want to remind you something I said earlier, which is just because you come into contact with a cold or flu does not necessarily mean that you will come down with, that is be infected by, a cold or flu. Whether or not you come down with a cold or flu is, of course...Dependent on whether or not you come into contact with it. You can't catch a cold or flu that you've never come into contact with, just like you can't get eaten by a shark if you never go in the ocean. However, the probability of coming down with that cold or flu, of it getting past your immune system barriers and infecting you is going to be strongly dictated by the different aspects of your immune system, for which there are three major aspects, which we'll talk about next. And of course, the things that you do to bolster those three aspects of your immune system. Okay. Let's talk about

9. 30:43 – 39:33

   Immune System, Physical Barriers

   1. AHAndrew Huberman30:43

      your immune system, and I have to confess that even though I've spent well over three decades being a student of and researcher of the nervous system, the immune system is, oh, so cool. And I say that because it has this incredible elegance and logic to it. It basically consists of three major lines of defense. There's a physical barrier, or rather, a set of physical barriers that exist between the organs of your body and the outside world, and you're probably immediately thinking, "Skin." And yes, indeed, it includes your skin, but also some interesting things, like the mucosal lining of your nose and mouth, and even some of the liquids that are on the surface of your eyes. We'll talk about those in a moment. Then there's a second line of defense, which is for any virus or bacteria or fungus, for that matter, but today we're talking about viruses, colds and flu viruses, any viruses that get past the physical barrier of your skin and the mucosal lining of particular regions of your body. Well, then you have what's called the innate immune system. The innate immune system is this very generalized response system. It's general in the sense that it deploys a basic set of neurochemicals that are not specific to the particular virus that's made it into your body. So not only is it not specific to a particular serotype of the cold or a different type of flu virus, but it's not even discriminating between cold or flu virus. This thing we call the innate immune system is a generalized response system to go and combat viruses. So it could be a cold, it could be a flu, it could be a bacteria, it could be a fungus. It could even be a physical object, and your innate immune system responds by saying, "Okay, let's go deal with this." Now, the third component of your immune system is what's called the adaptive immune system, and I alluded to this aspect of your immune system a little bit earlier. The adaptive immune system is the aspect of your immune system that recognizes, because the innate immune system told it, that something has infected the body at some level, at some organ or set of organs, and there's an emergency. And the adaptive immune system goes in and in a very targeted way, figures out what sorts of proteins it needs to produce, that is antibodies, to combat that specific serotype of virus. Okay, so the immune system has a physical barrier component, and it's not just skin, some other things as well. You've got your innate immune system, which is this generalized response system, and then there's the adaptive immune system. Let's talk about the physical barrier component first, and this is actually a good opportunity for us to just take a brief step back and realize that anytime we're talking about our physiology, there's going to be a mechanical set of features and there's going to be a chemical set of features. So right now, we're talking about the immune system and the mechanical feature or the physical feature of the immune system is this barrier between the organs of our body and the outside world, and the most obvious of those is the skin. You are contained in this bag of stuff that we call skin. The skin isn't just for putting clothing on and for adorning with jewelry or tattoos, if that's your thing, watches, et cetera. Your skin is a living organ in and of itself. I think we're most accustomed to thinking about the heart and the lungs and the liver and the brain as organs of the body, but the skin is an organ of the body as well. It has a bunch of different layers of cells from the outside to the inside. Actually, the skin cells themselves are made in the deeper layers of the skin, and they migrate out towards the surface of the skin, and at the surface of the skin, on top of those cells and made by those cells, are different types of chemicals that actually serve as antibacterial and antiviral agents. Meaning if a cold virus or flu virus or other type of virus lands on the skin, it can neutralize and kill that virus. So your skin is a very important physical barrier against viruses, such as the cold or flu virus, getting into your body and infecting other cells and tissues. Now, your skin is not contiguous, meaning there are holes in it. So let's think about those holes for a second. As we go from head to foot, it's pretty obvious that your eyes have these two openings, and those are openings in your skin, right? As you open your eyelids, beneath there are your corneas, the shiny part of your eyes, and then a little bit further back, at the back inner lining of your eyeball, you have a very thin three-cell layer thick piece of tissue that we call the neural retina. And I say this because the neural retina is actually a piece of your brain. So you have two pieces of brain that line the back of your eyes, and that's the light-sensing tissue in the back of your eyes. Now, I say this because what this means is that it's a very short distance between the opening of your skin that we call your eyelids and your brain. Now, most of the brain, of course, is contained in the cranial vault within what most people call the skull, but your brain isn't far away from those openings that we call your eyelids. So as a consequence, on the surface of your eyes, those corneas, the shiny part of your eyes on the outside, there are a bunch of different chemical features. There are tears that are made by your lacrimal glands, but there are also a lot of antibacterial agents that actively kill off stuff that could potentially infect your body, could make it into your body, maybe even into your brain. If you've ever woken up in the morning and you have some crust on your eyes, and you go, "Look at that crust," that kind of yellowy stuff. Sometimes it's yellow. I know this is kind of gross. That's actually dead bacteria that your eyes have successfully defeated during your night's sleep. So when you wipe those away, you're taking the casualties of a war that you won during your night's sleep, and you're whisking those away.Now, as we descend a little bit further down the face, there are, of course, the nostril openings, and the nostril openings tend to be kind of sticky, right? They're moist, sticky, and warm. All right, you don't have to put your fingers up them right now. You just know they're moist, sticky, and warm. Get your fingers out of your nose, please. The mucosal lining of your nose is actually a very important substance that is sticky in order to trap viruses, such as colds and flu viruses, and then chemical components within the mucosal lining can neutralize them. That's the best-case scenario. There are, of course, scenarios in which the cold or flu virus takes residence in your mucosal lining, and it can make its way back into your sinus passages and can then infect other cells and tissues of your body because the virus replicates and spreads throughout the body. And then going a fur- little bit further down, I realize this is obvious, you have your mouth. And what's really interesting is that your mouth also has mucosal lining, which is sticky, and it has chemical components to neutralize incoming viruses. But we know that the type of mucus and the type of bacteria that live in your nose and mouth, that, by the way, are very healthy for you and encourage healthy immune system function, that is, act as ways to neutralize viruses within your nose and mouth, are very different. So your nose and your mouth may seem similar at the level of, "Okay, well, it's warm and sticky in there. There's mucus," but they are very, very different tissues. In fact, if you think about your mouth, it's this incredible structure that not only lets you eat and breathe in and out through, although I suggest most people be nasal breathers for most of the time of their day and night if you can. Of course, sometimes you have to mouth breathe. But keep this in mind, that you have this big opening in the front of your face, and bacteria are getting in there all day long. Viruses are getting in there all day long, and in most cases, you are successfully combating those viruses and bacteria because the mucosal lining of your mouth, and your nose for that matter, and the microbiota, those little microorganisms that have taken residence in your nose and mouth, are helping to contribute to fight off bacteria and viruses, provided the microbiota there are diverse and are of the type you want, which we'll talk a little bit more about later. And then descending further down the body, of course, there are other openings into your skin barrier, namely the urethra of the penis or vagina and, of course, the vaginal canal. So the genitals, of course, have their own mucosal lining, and as you can imagine, it is distinct in terms of its physical makeup and its chemical makeup from the mucosal lining of your nasal passages and mouth. And then, of course, we have the rectum and anus, which is the outflow pathway of your intestines, which are post-digestive. And there, too, you have a mucosal lining for which, yes, certain types of viruses and bacteria can infect that area, but what we know is that the primary entry sites, the most common ways in which colds and flus get into your body, the way they breach that physical barrier that we call your skin, is through your eyes, your nose, or your mouth. And there are a lot of data, some of which conflict, and frankly there need to be more data in order to really resolve this, but it seems like the primary entry site for viruses to get into the body tends to be the eyes or the mouth. And we can get into some of the reasons why that would be so, but if you think back to our conversation about the way that colds and flus exist in the world, either as aerosols or on surfaces of objects or on surfaces of skin, well, then, what I'm about to tell you next will make it oh-so-obvious why the eyes and the mouth are the primary sites of entry for colds and flus, and if you keep that in mind, there's a good chance you can avoid a lot of colds or flus that you would otherwise

10. 39:33 – 45:14

    Tool: Social Connection & Touch, Avoiding Flu & Cold

    1. AHAndrew Huberman39:33

       catch. Okay, so before I talk about the important roles of the innate and the adaptive immune system in keeping colds and flus at bay, I'll tell you that you have a problem, and that problem is that you tend to touch your eyes very often. In fact, you tend to touch your eyes most often after you've shook somebody else's hand. Now, why am I picking on you? Well, in fact, I'm not. I'm picking on all of you, and I'm picking on myself included, because there have been several studies now, primarily from Noam Sobel's lab at the Weizmann Institute, showing that when people encounter another person and they shake their hand, they either touch their eyes or touch another region of their face very close to the eyes or that they touched their hand to their mouth. Now, there are a bunch of theories as to why people do this. There's the idea that people are actually sniffing their own hand and, in particular, sniffing their own hand more often after they shake someone else's hand as a way to detect what chemosignals exist on the other person. Not necessarily conscious smelling of the other person's smell, but rather some sort of unconscious mechanism by which we take the chemicals of the person we come into contact with and we bring them to our nose, our eyes, or in some cases, our upper lip, and that our olfactory system, that is, the neurons that exist just behind the back of our nose, are processing that information and getting all sorts of important information about how stressed the other person is, their hormones, uh, whether or not we recognize them, the fact that they are different from us. That's right. Uh, we are also smelling ourselves all day long. Noam's lab has shown this, that people are kind of walking around in their own odor cloud. We tend to touch our armpits. We tend to touch different aspects of our body, yes, and smell ourselves multiple times throughout the day. This is all being done unconsciously, or I suppose some people are doing it consciously, and that there's a lot of information about our physiology and health, and when we do this after shaking somebody's hand, that there's a lot of information about the other person's physiology and health that our nervous system, our olfactory system, and deep parts of our brain that are involved in primitive-type behaviors but also some pretty sophisticated behaviors are taking into account. Now, Noam Sobel was a guest on the Huberman Lab podcast. I encourage you to check out that episode if you have time. It's a fascinating voyage into the olfactory system and not just conscious smelling or sniffing of things where we go (sniffs) "Oh, that smells good," or, "That smells bad," or, "That person, you know, is somebody I want to mate with or hang out with or avoid." It's also unconscious processing of so-called chemosignals, chemical signals. But the reason I'm bringing up these studies now in the context of colds and flus and how to avoid getting colds and flus is as a reminder that we are...... Pretty much wired to contact our own face with our own hands at the level of our eyes, nose, and upper lip, and around the eyes, very shortly after we touch somebody else's skin. And if you are mindful of it, you can actually avoid bringing colds or flus to your face. Now, in doing so, are you going to short circuit a bunch of other important biological processes involved in understanding what's going on in your environment because you're not bringing in those smells? I suppose that's possible. But with respect to avoiding colds and flus, it seems like a pretty good trade-off to me. So the point that I'm trying to make here is that in order for you to catch a cold or flu, that cold or flu virus, the little particles of cold and flu virus, need to make it into your body and the primary entry sites are eyes, nose, mouth. And the primary actions by which we bring colds and flu viruses to our eyes, nose, mouth are by touching other people or by touching other surfaces that have cold or flu virus. Just to remind you, cold virus can exist up to 24 hours on a given surface. Flu virus tends to die off after about two hours on a given surface, and we're bringing that to our face. We are literally bringing the virus to ourselves. So a little bit more conscious awareness about that fact means that you can probably avoid colds and flus to some extent. How much? Well, it's unclear. It's unclear because, as you recall, some people have and are passing along cold or flu virus prior to any symptoms. And, of course, it's possible that you can walk into an aerosol cloud of cold or flu virus even if a person isn't there and you don't come into contact with them. But some conscious awareness of these routes of passage for the cold or flu virus, I do believe, can reduce the probability that you will catch a cold or flu. And, of course, I'm not encouraging people to never touch. Touch is an important part of social connection and social bonding. But if you start to think about these portals of entry for the cold and flu virus into your body, well, then you, you know, perhaps might think twice before, you know, hugging someone, kissing them on the cheek, during a time in which you're trying to actively avoid getting the cold or flu. Now, I feel a little bit funny about sharing this information because, again, I don't want to encourage people to always be at, you know, arm's distance, you know, and, uh, you know, fake fist bumping, you know, keeping a gap between them. Again, touch is an important component of social connection. But since today's topic is colds and flus and how to avoid getting colds and flus, just like you can't get eaten by a shark if you don't go in the ocean, there's a much lower probability that you're going to get a cold or flu if you're not touching a lot of hands and bringing those hands to your eyes, nose, or mouth. I suppose one way around the sort of, "Do I hug, do I shake hands" thing is to just be conscious of the fact that when you shake somebody's hand that you're very likely to touch your eyes or face within the next 30 seconds or so. And maybe you end up being that person to put some hand sanitizer on your hands. Sometimes that can feel a little awkward to do that right in front of somebody, you know? It's kind of sending a signal like, "Hey, I don't want you to infect me." But guess what? You don't want them to infect you. Okay, let's

11. 45:14 – 53:13

    Innate Immune System

    1. AHAndrew Huberman45:14

       imagine that a cold or flu virus makes it into your system. It breaches the physical barrier of your skin and mucosal lining. Now, you have in mind all the different ways that could happen and all the different ways that could be prevented. But we are starting at a point here, a hypothetical point, whereby that cold or flu virus has made it into your body. Your immune system has an absolutely exquisitely sophisticated way of knowing you versus other. Meaning, cells within your body that are of you and cells of your body that are from other organisms or viruses from the outside world. And when viruses, such as a cold or flu virus, are detected in your body, your body might not even recognize that it's a cold or flu virus. It might not even recognize that it's a virus at all. It just knows that this thing that's in me is of other. "It's not me. I've never seen it before. This is not me. These are not my cells. These are not the chemicals that I'm producing." And your immune system is amazing in that way, and when it occurs, your innate immune system launches a response. What is that response? Well, first of all, the response is very rapid, right? Cold or flu makes it into your body and your innate immune system immediately, or near immediately, launches an attack on that invader or invaders. Because as soon as the virus gets into your body, it's going to start replicating as quickly as it can. What happens? White blood cells that your body produces will go to the sites where those viruses are, and the- by the way, those viruses are basically getting into cells of your body and then hijacking the genetic machinery of those cells in order to replicate within those cells, and then exit those cells and then go infect more cells. That's how these viruses work. Your body's making white blood cells, things like neutrophils, natural killer cells, macrophages. These are what we call effector cells that act as a kind of ambulance system and go to the sites that those viruses exist and the cells that they've infected and start trying to physically barrier them in and also use specific chemical mechanisms to neutralize and kill those viruses. Again, any time you're thinking about biology, think mechanical features and chemical features of a response. Now, a key component of the innate immune system is what's called the complement system. Not compliment like, "Oh, you look very nice today," but complement, okay? The complement system which exists in the plasma within your blood. These are chemicals in your bloodstream that go and mark specific cells that have been infected, or viruses, with a signal, a chemical signal that essentially looks like an "eat me" signal to these other cell types of your immune system, such that those natural killer cells go through the body and go looking for the cells that have this "eat me" signal on them and try and destroy those particular cells. The other thing that your innate immune system does is that the cells that have been infected and that are undergoing damage, remember they have cold or flu virus within them and they're hijacking the cellular machinery of those cells and using it to produce their own virus, more of the virus. And as a consequence, the genetic machinery of those cells is not able to do a bunch of other things that it normally can do, or at least not as well. Well, those cells that are really hurting release a "help me"... signal. And then, in response to that help me signal, your immune system releases what are called cytokines. Things like interleukin one, interleukin six, tumor necrosis factor alpha. Just fancy nerd speak names for different types of molecules that go to the site of infection and try to help or assist to remove that infection. And they also try to assist the repair of the cells that have been infected by those viruses. Now, one of the mechanical or physical consequences of these chemical signals, like interleukin one, interleukin six, TNF alpha, again, those are all cytokines, being drawn to a particular cell or region of cells that have been infected, is that it creates some physical swelling of the area. It impacts the vasculature, the veins and capillaries that feed that area, and in response to that, they put more blood there, so you get some swelling. Or you'll get, in some cases, the release of histamines, right? We think of antihistamine drugs. Well, histamines are an aspect of your immune system, they move around in your body in these really cool cells called mast cells, M-A-S-T, mast cells. And when the histamines are released, that area becomes kind of hot and swelling. It's what we call edema. And that whole area is marked as really a site, just like a crash site on the side of the road, it's like, "Hey, we've got 'eat me' signals to get the debris and the bad stuff out of here, try to get those viruses out of here." We've got "help me" signals to try and help the injured cells, just like you would try and help people at a car crash. And there's a bunch of swelling, so there's additional blood flow. Sometimes there's some other physical features as well. Now, the important thing to know is that the innate immune system is very fast and it is agnostic to the type of infection. In fact, it doesn't even matter if it's a bacterial, physical, fungal, or viral infection. But it certainly isn't paying attention to the exact serotype of cold virus or whether or not it's an H1 influenza or another type of influenza. So the way to think about the innate immune system is that it is a very fast and non-specific response to a viral or other type of invader. Now, that's all a bunch of biology, but if you think about it, let's imagine a scenario where you go to a party, hang out at the party. You don't see anyone coughing or sneezing, but maybe one person there has a cold virus or they have a flu virus and they aren't even aware of it. They're not gonna come down with symptoms for another day or so. You talk to that person, you shake hands, maybe you touch your eyes, maybe you don't. But you're exposed to that cold or flu virus. You go home, you go to sleep, you wake up the next morning, you feel fine. And then sometime the next afternoon, you know, you start to feel a little tickle in your throat or you start to feel just a little bit of fatigue or malaise. Do you have that cold or flu? Well, possibly. Okay. We don't know for sure, but assuming that that cold or flu virus did indeed make it into your system, then your innate immune system is starting to create a set of responses that we talked about a moment ago. But it also tends to impact things at the level of your brain such that you kind of feel like, "Ah, you know, I don't feel quite right. I feel like a little bit, ugh. I don't feel great." And there are a lot of reasons why you would feel that way, and we'll talk about those reasons a little bit later. But does that mean that you're necessarily coming down with a cold or flu? Well, technically yes. Your innate immune system is deployed to fight this foreign viral invader. But whether or not you actually get a full-blown cold or flu, or put differently, how severe that cold or flu infection is depends on whether or not your innate immune system can fight off that cold or flu at the outset. And indeed, there are many cases, we believe, where you get exposed to a cold or flu, it makes it into your body, but your innate immune system is sufficient to beat it, to fight it back. This is one of the reasons why it's so important that if you're starting to feel a bit under the weather and you think you're coming down with a cold or flu, that you do certain things in order to make sure that your innate immune system is both ready and that it can launch a full-scale attack on that cold or flu virus. We're gonna talk about how to do that a little bit later. I'm not trying to withhold. It's just, it's important to understand that just because the virus makes it into your body doesn't necessarily mean that you're gonna get a full-blown cold or flu. And in fact, that innate immune system sometimes is sufficient to prevent that cold or flu from replicating enough that you get the full-blown set of symptoms. And that's kind of an ideal scenario. So we're definitely gonna talk today about what to do if you start to feel a little bit of malaise. What to do if you discover that, oh, you know that person I was hanging out with at the party the night before? They're really sick with a cold or flu. Because there are things you can do to increase the probability that your innate immune system can handle the battle sufficiently such that you never have to get to the next component of the immune response, which is the adaptive immune response.

12. 53:13 – 54:15

    Sponsor: InsideTracker

    1. AHAndrew Huberman53:13

       I'd like to take a quick break and thank our sponsor, InsideTracker. InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and help you reach your health goals. Now, I've long been a believer in getting regular blood work done, for the simple reason that many of the factors that impact your immediate and long-term health can only be analyzed from a quality blood test. A major problem with a lot of blood tests out there, however, is that you get information back about metabolic factors, lipids and hormones and so forth, but you don't know what to do with that information. With InsideTracker, they make it very easy, because they have a personalized platform that allows you to see the levels of all those things, metabolic factors, lipids, hormones, et cetera, but it gives you specific directives that you can follow that relate to nutrition, behavioral modifications, supplements, et cetera, that can help you bring those numbers into the ranges that are optimal for you. If you'd like to try InsideTracker, you can go to insidetracker.com/huberman to get 20% off any of InsideTracker's plans. Again, that's insidetracker.com/huberman. Okay. So

13. 54:15 – 1:00:19

    Adaptive Immune System; Lymphatic System

    1. AHAndrew Huberman54:15

       the third layer of your immune system is your adaptive immune system, and this is an amazing aspect of you. Okay. The stuff we talked about up until now, the physical barrier, the innate immune system, so, so cool. But the adaptive immune system is really a mind-blower. The most important thing to understand about your adaptive immune system is that, as the name suggests, it-Its job is to create antibodies specific to the very intruder that made it into you and infected your cells. The very specific serotype of cold virus, the very specific type of influenza. Such that, you defeat that virus, but then in an amazing way, your adaptive immune system also maintains a memory of that battle and keeps within your body, believe it or not, within a population of stem cells, which are cells that can rise to more cells, such that if you ever encounter that same serotype of cold virus or same strain of influenza again, that your antibodies can immediately neutralize that cold or flu virus. The adaptive immune system has the ability to make proteins that have a particular shape on their surface that matches the shape of the thing that your immune system is trying to kill. Now, the adaptive immune system has two basic phases. In the first phase, the adaptive immune system makes these things called immunoglobulins, IGs. And the immunoglobulins come in different forms. There's IgG, there's IgM. There are other types of IGs as well. For sake of today's discussion, know that the initial wave of antibodies that the adaptive immune system makes are of the IgM variety. And the IgM antibodies can travel to, and latch onto the surface of the cold or flu virus. And it matches it pretty well. It's not perfect, but it matches it pretty well. Think about, uh, for instance, a particular serotype of cold virus or the H1N1 flu virus having, you know, a very particular contour on its surface. The IgM approximates that contour such that it's better at fighting that cold or flu virus than is the innate immune system, but it's not a perfect fit. However, the adaptive immune system doesn't stop with the production of those IgMs. The adaptive immune system takes that information about how precise or imprecise that fit is between the IgM antibodies and the surface of that particular cold or flu virus, and then in an amazing way, sends signals back to the stem cell populations in the bone marrow and other tissues, and then more antibodies come out of the IgG variety. And the IgG proteins are very specific to the shape of that particular cold virus or flu virus such that the IgGs then can define to and neutralize those viral particles, okay? So when we talk about the immune system, we're talking about a physical barrier that if it is breached, a cold or flu virus takes residence and starts to replicate, the innate immune system launches a generalized attack on that cold or flu virus, and then the adaptive immune system kicks in, usually a couple days later. First with the production of antibodies that are pretty specific to the particular virus that happened to make it into the body and infect cells, but then there's a second wave of production of antibodies, and those antibodies are incredibly specific for that particular cold or flu virus, and as I mentioned earlier, the adaptive immune system then acquires a memory of the specific fit between a given antibody that it made and the viral invader and the successful battle that those antibodies waged on that viral invader. And that memory is maintained such that if the next week or the next season you encounter the exact same serotype of cold virus or same type of flu virus, well then you already have antibodies ready to be deployed. Sometimes the antibodies continue to circulate in your system. Sometimes you need to generate more of them, and the immune system is that amazing. It can actually send a message back to that stem cell population in the bone marrow or elsewhere, say, "Hey, listen, this virus that we beat a few weeks or months or years back, it's back. We need more antibodies." And boom, your adaptive immune system churns those antibodies out and kills the virus. Now as a final point about the immune system, I've been talking a lot today about cells traveling to and killing viruses and sending signals, "Eat me, help me," et cetera. It's important to understand that while cells can migrate through the body, a lot of what we're talking about here is the movement of proteins through the vascular, through the blood system of the body. But there's another system that's very important for all of this that's collaborating with the vascular system, and that's the lymphatic system. And we don't have time to go into a whole lecture about the lymphatic system, but suffice to say the lymphatic system can pull stuff from the blood such as viruses, but also cells that have been beaten up or cells that have been eaten and are contained within other cells such as macrophages, and it can do some filtering of those different cell types and it can produce its own useful chemicals that then can be reintroduced to the bloodstream in order to help combat the infection. Now this becomes very important when later we talk about how specific forms, intensities, and durations of exercise can increase the ability for your innate immune system to combat infections so that your adaptive immune system perhaps doesn't even have to get involved in the battle because your innate system handled it. There are data to show that exercise of sufficient intensity and duration, but not excessive intensity and duration, can recruit the lymphatic system and recruit or increase the activity of the innate immune system even in the absence of an infection such that if you go to that party and you encounter that person with a cold or flu, you can defeat that cold or flu virus at the outset and never have to deal with making antibodies to that cold or flu virus at all. Okay, so now you have

14. 1:00:19 – 1:06:19

    Tools: Enhance Innate Immune System

    1. AHAndrew Huberman1:00:19

       a fairly sophisticated biological understanding of what colds are, what flus are, and the way that your immune system works to fight off viruses like colds and flus. So with that in mind, I think now is the appropriate time to start talking about what the scientific peer-reviewed research says about how to allow your immune system to function at its best such that you can combat colds and flus. Meaning...... if you are exposed to a cold or flu, that is, if it breaches that physical barrier of your skin and the mucosal lining of your nose, your mouth, or it gets into your eyes, that you stand the greatest chance of defeating that cold or flu at the level of your innate immune system, such that your adaptive immune system never even has to respond to it by creating all those specific antibodies. Now, fortunately, there are a lot of different things we can do to improve the function of our immune system. In fact, I feel like any time the winter months roll around, we start to see the same list of things surface online and in the press. And I don't want to diminish these things. They are, in fact, the bedrock of maintaining and enhancing the function of your innate immune system. So what are those? Well, some of these will be pretty obvious, things like getting enough quality sleep each night. We know, for instance, that if you're sleep-deprived, so especially if you stay up all night, but certainly even if you only get 50% or 75% of your sleep requirement, that your innate immune system is going to suffer. It's not going to be as effective at combating flus or colds. In addition to that, we know that exercise of specific type and specific duration and specific intensity can serve to bolster the innate immune system, and we'll talk about the specific exercise protocols that can best achieve that. We also hear, and it's absolutely true, that we need adequate nutrition. If we are in a caloric deficit, for instance, if we're trying to diet through the winter months, which many people try to do, that can place our innate immune system in a bit of a compromised state. That said, things like intermittent fasting or even longer-duration fasts have been implicated, and here I really want to underscore implicated, in brief improvements in the function of the innate immune system. However, extended fasts or not eating enough calories to maintain body weight for many, many days in a row can actually compromise the function of the innate immune system. I'll go into this a bit deeper in a moment. And then, of course, we hear about stress, that we're all supposed to regulate our levels of stress, not get too stressed, and here I have to put an asterisk next to those statements because yes, indeed, chronic stress, meaning stress that continues day after day after day, or even short periods of stress that impede our ability to sleep at night, can indeed reduce the functioning of our innate immune system. However, it's also clear that short bouts of stress, provided that they don't inhibit our ability to sleep that night, can actually enhance the function of the immune system. And this is something that I don't think is talked about enough. You know, we hear so often that, quote unquote, "Cortisol is bad. It's a stress hormone." Listen, cortisol is fantastic provided that it is elevated early in the day and not late in the day or evening. Also, cortisol does have thresholds beyond which, if it's too high, can be bad for us. But it's also the case that if cortisol levels are too low, that's bad for us, and it's especially bad for the functioning of our immune system because glucocorticoids, of which cortisol is, have an important role in activating those natural killer cells of the innate immune system. They are one of the primary signals by which those interleukins, like interleukin-1 and interleukin-6, are deployed in our body. And so very often, we'll hear, "Stress increases inflammation," and indeed, interleukin-1, interleukin-6 are pro-inflammatory. You might think, "Oh my goodness, I don't want that. I don't want cortisol. I don't want these interleukins elevated." But guess what? The inflammation response is also an important component of that innate immune system that allows us to combat infections. So in trying to keep our innate immune system tuned up, I realize that's not a biological statement, "tuned up," but keep our immune system functioning at its best, we want inflammation available as a tool to combat infection. We want cortisol available as a way to activate that inflammation and other aspects of our immune system. We just don't want so much cortisol and so much inflammation that we can't sleep and that our gut microbiome suffers, and that brings me to the other component that's important for the basic functioning of your innate immune system so that you can be at your strongest when you inevitably encounter those cold and flu viruses. Why do I say inevitably? Look, if you exist in the world, that is, if you live on planet Earth, you are going to be bombarded with different viruses and bacteria and funguses and all this stuff throughout your days. And yes, in those winter months, because people are spending more time indoors, and they're touching each other and surfaces more, breathing on each other more, sneezing on each other more, and so on and so forth, there is more propagation of colds and flus. So if we take a step back and we ask, "How can I have my immune system as strong and ready as possible to combat cold and flu viruses?" we get to those basics. It's make sure you're getting enough quality sleep each night. How much is enough? However much you need in order to not feel sleepy during the day, except maybe the requirement for a short nap of anywhere from 10 to 30 minutes. Not everyone requires that, but that's perfectly normal to have an afternoon dip in energy that can be restored with a short nap or non-sleep deep rest. We'll provide links to non-sleep deep rest and other tools in the show note captions that, you know, are zero-cost tools to allow you to recover your energy. Some people just simply take a nap and that sort of thing. If you want tools for improving your sleep and making sure that you're getting enough quality sleep each night, we will also provide a link to our zero-cost sleep toolkit that details that in PDF form and just lists out the things that you can do or take if that's your choice and so on and so forth. And of course, we've done episodes on quality nutrition and what that means. We've done episodes on stress and how to combat stress, and we've done episodes on the so-called gut microbiome. But

15. 1:06:19 – 1:10:58

    Tool: Microbiome & Nasal Breathing

    1. AHAndrew Huberman1:06:19

       right now, I just want to mention that the gut microbiome, which are the trillions of little microbacteria that interact heavily with the immune system and help support the immune system, you want to keep the gut microbiome healthy. So you'll notice that we include some tools related to the gut microbiome here in a moment. And, and this is very important, keep in mind that the microbiome doesn't just exist in the gut. So often these days we hear about the gut microbiome, and I'm oh so happy that the gut microbiome is getting the attention that it deserves in the context of mental health, physical health, and performance, but we can't forget that the microbiome also exists on the surface of the eyes.... and in the nasal passages. And indeed, the microbiome that's specific to the nasal passages, as I mentioned before, is very different from the microbiome that exists within the mouth. And the microbiome that exists within the mucosa of the nasal passages seems to be the most effective at combating any viruses that we encounter, especially cold and flu viruses. So while ideally, you would never encounter a cold or flu virus, we know that if the cold or flu virus is going through the nasal passages, you stand the greatest chance of combating that particular cold or flu. So, what does that mean? This is where I get to make a strong push for being a nasal breather. Certainly in sleep, you want to be a nasal breather. But also throughout the day, unless you're speaking, or unless you're exercising hard enough that you need to breathe through your mouth, or unless you're eating, being a nasal breather is known to provide the right milieu, the right environment to keep that nasal microbiome at its healthiest, and to promote the diversity of microbiota in the nasal passages that can best protect you against colds and flus. And there are a growing number of studies that point to this fact. I'll provide a link to one that I like very much, which is entitled Alterations in Oral, Nasal, Pharyngeal Microbiota and Salivary Proteins in Mouth-Breathing Children. This is but one study pointing to the fact that being a nasal breather is a good thing. Mouth-breathing children and mouth-breathing adults, meaning children and adults that default to mouth-breathing, tend to get more infections of, of the upper respiratory tract, including colds and flus. Consciously focusing on nasal breathing is one of the best things that we can all do to combat any colds or flus that we might encounter. So earlier, we talked about trying to avoid touching your eyes, at least without washing your hands first or sanitizing your hands first after you meet somebody, keeping in mind that most people do that unconsciously. Here, we are also saying when you enter a room, you're hanging out with people, maybe you're waiting for public transportation, or you're at work or walking down the hallway, unless you are exercising hard, unless you are talking, try to focus on being a nasal breather. There are a bunch of other reasons to be a nasal breather as well, but this is one of the primary ones. And I'll provide a link to another reference, which is the book Jaws by my colleagues at Stanford, which talks about nasal breathing and the importance of nasal breathing. But also the degree to which children and adults open themselves up to increased levels of viral infections, as well as bacterial infections, but viral infections in particular, when they rely on mouth-breathing. And the incredible benefits of doing this very simple, zero-cost thing of whenever you can consciously remember to, breathing through your nose as opposed to breathing through your mouth. And just as an additional point about nasal breathing, because I can't resist telling you this, I just think it's so cool, such an interesting adaptation. When we breathe through our nose, we heat the air in a way that's very different from the way we heat the air when we mouth-breathe. And by heating the air that's coming into the nasal passages, it shifts the probability that cold or flu viruses will successfully embed in the mucosal lining and infect the underlying cells and get into the other cells and tissues of our body. So this whole thing about nasal breathing is important and effective at the level of temperature regulation of the milieu within the nose, and therefore the viruses that end up in the nose, as well as the mucosal lining, the chemicals made by the mucosal lining. And again, the nose is a very different place than the mouth. In fact, I'll provide a link to yet another paper, uh, which is entitled Human Nasal Microbiota. It's a really interesting paper. It's actually an interview with a scientist who's expert in the nasal microbiome, talking about how this structure within our nose really is the primary defense site by which we destroy potentially incoming viruses. So if it sounds overly simple, just breathe through your nose, it is very simple, but it's also very effective. Now, it's also

16. 1:10:58 – 1:16:13

    Tools: Enhance Gut Microbiome: Foods & Water Protocol

    1. AHAndrew Huberman1:10:58

       clearly the case that keeping your gut microbiome is advantageous for keeping your innate immune system at its most robust level of functioning. And I should mention that your gut microbiome isn't just about your stomach. You know, we hear the word gut and we think stomach. But it's actually the entire length of your digestive tract from your mouth out the other end. And different microbiota exist at different locations along that tract of mucosa. And there are a couple things that one can do in order to make sure that the gut microbiome is best supported along that entire length. The first one is that... And this was covered on the episode that we did with my colleague Justin Sonnenburg, who is a world expert in the gut microbiome. And that is to consume anywhere from two to four servings of low-sugar, fermented foods per day. So things like sauerkraut, things like kimchi, things like kefir, things like kombucha. It can be a little bit of work to figure out which of these you like and which ones you're willing to consume on a regular basis. But it's very clear that the brine, you know, that kind of, uh, salty solution around the sauerkraut... And by the way, when I say sauerkraut, what we're talking about here is the type that has to be refrigerated. It contains what are called live cultures, as opposed to the sauerkraut that can exist in the non-refrigerated portion of the store. Or pickles that also have that brine and that have to be kept in the refrigerator even before they're opened. And of course, things like yogurt, which have active live cultures. Those are the sorts of things that are going to best support the diversity of microbiota along the entire length of the gut microbiome, such that your gut microbiome can do its job in supporting your nervous system, but here, especially in the context of today's discussion, your immune system. Now, the low-sugar component of low-sugar fermented foods is important, because what we know is that if you're consuming yogurts with a lot of sugar, or you're consuming kombucha with high levels of sugar, or you're consuming pickles or...... sauerkraut that have a lot of sugar in them, you're probably gonna start to create some other issues related to the sugar. What you're really looking for are these low sugar fermented foods, and they can be a little bit tricky to seek out in the store, but they're usually there. And once you identify the ones that you like, you should really aim to get two to four servings of those per day. You can also consume a prebiotic or probiotic in the form of capsule form, things like AG1. Athletic Greens also contain prebiotic, probiotic. But it's very clear that consuming two to four servings of low sugar fermented foods per day is among the best ways to promote health of the gut microbiome, and that the gut microbiome is so, so important for keeping the innate immune system thriving, such that it can combat the colds or flus that are trying to bombard your system. Now, there's another tool that you can use to enhance your gut microbiome. I have to warn you, this one might make a few of you, um, cringe a little bit. But this is one that I actually started doing about four months ago. Um, it's an interesting one. It kind of dates back to some older, quote-unquote, "traditional" medicine practices, but it makes really good logical sense. To be fair, I'm not aware of any randomized control trial exploring the use of this protocol, but it's so simple and completely cost-free, and it stands so strongly on the logic of how the gut and oral microbiome work that, frankly, I started doing it. And, you know, whether or not it's placebo effect or not, I don't know, but I feel better and it's so easy to do, and it stands to potentially improve the function of your gut microbiome enough that I figured I would at least share it with you and then you can decide. So what this protocol essentially consists of is before you go to sleep at night or in the morning, you pour yourself a little bit of water, whatever water you happen to consume, just clean, clear water. And then you take a sip of that water when you wake up in the morning and you swish it around in your mouth and then you swallow it. Now, for those of you that are like, "Oh, gross," let's think about this. Is it really gross to swish a little bit of water around in your mouth and then swallow that water when you first wake up? Prior to brushing your teeth, of course. Well, it might seem gross to you, but throughout the night when you're sleeping, especially if you are a nasal breather while you sleep, the environment within your mouth is such that you're breeding a lot of bacteria. You are creating all those little microbacteria that potentially can inhabit your digestive tract and provide at least some of the substrate for the microbiota in your digestive tract to thrive. And if that seems gross to you, keep in mind that's what having a healthy gut microbiome really is all about. So the protocol is very simple, it's zero cost. You take a swig of water, swish around, and swallow it. Uh, oddly, it doesn't taste bad. Um, in fact, it'll just taste like swallowing. Um, and in fact it tastes like

Episode duration: 2:05:48