How to Use Cold & Heat Exposure to Improve Your Health | Dr. Susanna Søberg

(music plays) 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. Susanna Søberg. Dr. Susanna Søberg completed her doctoral thesis work at the Center of Inflammation and Metabolism and the Center for Physical Activity Research at the University of Copenhagen in Denmark. Her research has focused on how deliberate cold exposure and deliberate heat exposure can be used to enhance human metabolism. She is the first author of a seminal study which discovered the minimum thresholds for deliberate heat and deliberate cold exposure for increasing brown fat thermogenesis, which is essentially a mode of increasing heat production and metabolism in the body, and for establishing actionable protocols that can be used outside of the laboratory to improve metabolism and human health. Dr. Søberg's research was published in the journal Cell Reports Metabolism in 2021, adding to a long and important history of research focusing on the role of cold and the role of heat in altering various aspects of the body's physiology, including hormone health, metabolism, and changes in neurotransmitters such as dopamine and epinephrine. In fact, today's discussion with Dr. Søberg focuses on the role of deliberate heat and deliberate cold exposure on metabolism, but it also includes discussion of the effects of cold and heat on things like neurotransmitter production, namely dopamine and epinephrine and norepinephrine, the so-called catacholamines which strongly impact mood and metabolism. In addition, Dr. Søberg answers many common questions about deliberate cold and deliberate heat exposure, including, for instance, the difference between cold showers versus cold immersion up to the neck versus total body cold immersion, including whether or not going back and forth between heat and cold changes fundamentally the way that heat and cold impact the metabolism, hormones, and neurotransmitter production. And we talk about almost every single nuance and variation on deliberate cold and deliberate heat exposure protocols as it relates to the underlying science, in particular how cold receptors at the level of the skin are impacted versus cold reception and perception at the level of the brain, and how all of that impacts systems of the brain and body relating to mental health, physical health, and performance. Based on her scientific research and academic training, as well as her understanding and use of deliberate heat and deliberate cold exposure protocols, Dr. Søberg is considered one of the world's leading experts on these topics. In fact, she is the author of a recent book entitled Winter Swimming, which is, I have to say, a terrific book because it breaks down chapter by chapter the different aspects of deliberate heat and deliberate cold into its various constituent parts, including cold acclimization, the cold shock response, dangers and safeties of cold water, the impact of cold and the impact of heat on various aspects of human health, as well as specifics relating to sauna versus ice versus cold swimming, showers, et cetera. It's a very thorough read and a very easy and accessible read that, if you are interested in deliberate cold or deliberate heat exposure or both, will allow you to embrace those protocols with the greatest degree of confidence that you're going to obtain the specific endpoints that you're interested in, and to do so safely. 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 Plunge. Plunge makes what I believe is the most versatile at-home self-cooling cold plunge for deliberate cold exposure. I've talked numerous times on this podcast about the many benefits of deliberate cold exposure, and indeed, today's episode is focused entirely on the benefits and the science of deliberate cold exposure. Plunge uses a powerful cooling filtration and sanitation unit to give you access to deliberate cold exposure in clean water whenever you want. As we will discuss during today's episode with Dr. Susanna Søberg, deliberate cold exposure, especially deliberate cold exposure done up to the neck in water, can be used to achieve a number of important endpoints related to mental health, physical health, and performance. I've been using a Plunge for more than two years now, and I can tell you that it makes it very easy to get your deliberate cold exposure at home. It doesn't require much cleaning. In fact, it's very easy to keep clean, which is essential. You don't want bacteria and other things growing in your cold plunge. Basically, everything about the Plunge is made easy so that anyone, including myself, can get their deliberate cold exposure on a regular basis at home. If you're interested in getting a Plunge, you can go to Plunge, spell P-L-U-N-G-E, .com/huberman and get $150 off your cold Plunge. Again, that's plunge.com/huberman for $150 off. Today's episode is also brought to us by Maui Nui Venison, which I can confidently say is the most nutrient-dense and delicious red meat available. Maui Nui spent nearly a decade building a USDA-certified wild harvesting system to help balance deer populations on the island of Maui. The solution they built turns the proliferation of an invasive species into a wide range of nutrients-dense products, from butcher cuts and organ meats to bone broth and jerky. Their bone broth has an unmatched 25 grams of protein per 100 calories. Several guests on this podcast who are experts in nutrition have pointed to the value of getting at least one gram of quality protein per pound of body weight each day. With Maui Nui, that's very easy to do while eating delicious meals and getting it from a sustainable source. If you would like to try Maui Nui Venison, go to maui nui venison.com/huberman and get 20% off your first order. Again, that's maui nui venison.com/huberman to get 20% off. Today's episode is also brought to us by Thesis. Thesis makes custom nootropics, and nootropics is not a word that I like because it means smart drugs, and the brain doesn't have neural circuits for being smart, rather has neural circuits for focus, neural circuits for task switching, neural circuits for creativity, and on and on. Thesis understands this and designs custom nootropics designed to get your brain and body into a specific state in order to do the mental and/or physical work that's important to you, such as creativity or focus or clarity. If you'd like to try Thesis Nootropics, you simply go to their website...You fill out a brief quiz and they will design a custom starter pack so that you can assess which things work for you more or less well, and then they'll iterate with you over the course of the next few weeks or months to come up with the ideal nootropic kit for your needs. To get your own personalized nootropic starter kit, go online to takethesis.com/huberman. You can take that three-minute quiz, and they'll send you four different formulas to try in your first month. Again, that's takethesis.com/huberman and use the code Huberman at checkout to get 10% off your first box. I'm pleased to announce that I will be hosting two live events in September of 2023. The first live event will take place in Toronto on September 12th. The second live event will take place in Chicago on September 28th. Both live events will include a lecture and a question and answer period and are entitled The Brain Body Contract, during which I will discuss tools and science related to mental health, physical health, and performance, and I should mention that a lot of that content will have absolutely no overlap with content covered previously on the Huberman Lab Podcast or elsewhere. If you're interested in attending either or both of these events, please go to hubermanlab.com/tour and enter the code Huberman to get early access to tickets. Once again, that's hubermanlab.com/tour and use the code Huberman to access tickets. I hope to see you there. And now for my discussion with Dr. Susanna Soberg. Dr. Susanna Soberg, welcome.