How Smells Influence Our Hormones, Health & Behavior | Dr. Noam Sobel

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 my guest is Dr. Noam Sobel. Dr. Noam Sobel is a professor of neurobiology in the Department of Brain Sciences at the Weizmann Institute of Science. His laboratory studies olfaction and chemosensation. Olfaction is, of course, our sense of smell. Chemosensation is our ability to respond to chemicals in our environment. Today you are going to learn some absolutely incredible facts about how you interact with the world and other people around you. For instance, you will learn that humans can smell things around them as well as dogs can. In fact, humans are incredibly good at sensing the chemical world around them. You will also learn, for instance, that every time you meet somebody, you are taking chemicals from that person, either from the chemical cloud that surrounds them or directly from the surface of their body, and you are actually applying it to your own body, and you are processing information about that person's chemicals to determine many things about them, including how stressed they are, their hormone levels, things that operate at a subconscious level on your brain and nervous system, and that impact your emotions, your decision-making, and who you choose to relate to or not to relate to. You will also learn that tears, yes, the tears of others, are impacting your hormone levels in powerful ways. You will also learn that every so often, actually on a regular schedule, there is an alternation of ease through which you can breathe through one nostril or the other, and that alternation reflects an underlying dynamic of your nervous system and has a lot to do with how alert or sleepy you happen to be. The list of things that Dr. Noam Sobel's laboratory has discovered that relate to everyday life and that are going to make you say, "Wow, I can't believe that happens," but then go out into the real world and actually observe that that happens in ways that are incredibly interesting just goes on and on. In fact, his laboratory discovered that we are always sensing our own odors. That's right. Even though you might not notice your own smell, you are always sensing your own odor cloud, and throughout the day you periodically smell yourself deliberately, even though you might not realize it, in order to change your cognition and behavior. I first learned of Dr. Sobel's laboratory through a rather odd observance. That observance took place when I was a graduate student many years ago at UC Berkeley. At the time, Noam Sobel was a professor at UC Berkeley. As I mentioned before, he has since moved to the Weizmann. Well, I was walking through the Berkeley campus and I saw people on their hands and knees, but with their head very close to the ground, and their eyes were covered, their hands were covered, their mouths were covered, and only their nose was exposed. And what I was observing was an experiment being conducted by the Sobel Laboratory in which humans were following a scent trail. That scent trail was actually buried some depth underneath the earth, and yet they could follow that scent trail with a high degree of fidelity. It was from that experiment and other experiments done in Dr. Sobel's laboratory at Berkeley and at the Weizmann involving neuroimaging and a number of other tools and techniques that revealed the incredible power of human olfaction and humans' ability to follow scent trails if they need to. And that, of course, led to many other important discoveries, some of which I alluded to a few moments ago, but you are going to learn about many, many other important discoveries in the realm of olfaction and chemosensation that have been carried out by Dr. Sobel's laboratory through the course of today's episode. And by the end of today's episode, I assure you that you will never look at or smell the world around you the same way again. 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 ROKA. ROKA makes eyeglasses and sunglasses that are of 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 eyeglasses and sunglasses were designed with the biology of the visual system in mind, so no matter whether or not you're wearing them for sport, whether or not you're wearing them for work or for socializing, you can always see with crystal clarity. Their glasses are extremely lightweight, so most of the time you don't even realize that you're wearing them. I wear ROKA Readers at night and sometimes when I drive at night, and I wear ROKA sunglasses throughout the day, except, of course, I do not wear them for my morning sunlight viewing. If you'd like to try ROKA eyeglasses or sunglasses, go to ROKA, that's R-O-K-A, .com and enter the code Huberman to save 20% off your first order. Again, that's R-O-K-A .com and enter the code Huberman at checkout. Today's episode is also brought to us by Thesis. Thesis makes custom nootropics, and nootropics is a word that I do not like because it means smart drugs. As a neurobiologist, I can tell you that there is no neural circuit in your brain for being smart. There are neural circuits for focus, there are neural circuits for memory, there are neural circuits for creativity, and there are neural circuits for task switching. 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So if you go to the Helix website, you can take a very brief quiz, it only takes about two minutes, and answer questions such as, do you tend to sleep on your back or your side or your stomach? Do you tend to run hot or cold throughout the night? Maybe you don't know the answers to those questions. But they'll match you to a mattress that's ideal for your sleep needs. For me, that was the Dusk, D-U-S-K, mattress, which is not too firm and not too soft, and I've been sleeping on it for more than two years and it's the best sleep that I've ever had. If you'd like to try a Helix mattress, go to helixsleep.com/huberman. Take that two-minute quiz and they'll match you to a customized mattress and you'll get up to $350 off any mattress order and two free pillows. Again, if you're interested, you can go to helixsleep.com/huberman for up to $350 off and two free pillows. And now for my discussion with Dr. Noam Sobel. Dr. Sobel-