Huberman Lab
Behaviors That Alter Your Genes to Improve Your Health & Performance | Dr. Melissa Ilardo
Mon, 26 May 2025
My guest is Dr. Melissa Ilardo, Ph.D., professor of biomedical informatics at the University of Utah. We discuss the interplay between genes and behaviors, including how certain behaviors can improve resilience by changing gene and organ function, as well as natural selection events happening in humans today. We also discuss the immune system–related reasons people find the smells of potential mates attractive—or not. We explore how physical and psychological traits are passed from one generation to the next, and the specific behaviors that can influence gene expression to improve health and performance. Melissa explains her lab’s pioneering research on breath-hold training and how activation of the dive reflex through breath holding can significantly improve oxygen availability by changing spleen size and function. We also delve into the medical uses and ethics of gene editing to cure disease in both babies and adults. For those interested in genes and inheritance, human performance, immune system function, and natural selection, this episode illustrates the remarkable interplay between human nature and nurture. Read the episode show notes at hubermanlab.com. Thank you to our sponsors AG1: https://drinkag1.com/huberman Joovv: https://joovv.com/huberman Eight Sleep: https://eightsleep.com/huberman LMNT: https://drinklmnt.com/huberman Function: https://functionhealth.com/huberman Timestamps 00:00:00 Melissa Ilardo 00:02:35 Nature vs Nurture, Gene Expression, Eye Color 00:07:06 Sponsors: Joovv & Eight Sleep 00:10:24 Epigenetics, Trauma, Mutations; Hybrid Vigor, Mate Attraction 00:15:47 Globalization; Homo Sapiens, Mating & Evolution; Mutations 00:25:28 Sea Nomads, Bajau & Moken Groups; Free Diving, Dangers & Gasp Reflex 00:32:52 Cultural Traditions, Free Diving & Families; Fishing 00:35:36 Mammalian Dive Reflex, Oxygen, Spleen, Cold Water & Face; Exercise 00:42:43 Sponsors: AG1 & LMNT 00:46:00 Free Diving, Spleen, Thyroid Hormone, Performance Enhancement 00:52:00 Dive Reflex, Immune System; Swimming & Health; Coastal Regions & Genetics 00:55:17 Female Free Divers, Haenyeo, Cold Water, Age, Protein 01:03:20 Human Evolution & Diet, Lactase, Fat 01:05:07 Korean Female Free Divers & Adaptations, Cardiovascular, Pregnancy 01:10:13 Miscarriages & Genetic Selection; Bajau, External Appearance, Mate Selection 01:17:15 Sponsor: Function 01:19:03 Free Diving, Underwater Vision; Super-Performers & Genetics 01:25:01 Cognitive Performance, Autism, Creativity; Genetic Determinism & Mindset 01:36:30 Genetics & Ethics, CRISPR, Embryo Genetic Screening 01:44:36 Admixture, Genetics; Are Humans a Single Species? 01:49:39 Zero-Cost Support, YouTube, Spotify & Apple Follow & Reviews, Sponsors, YouTube Feedback, Protocols Book, Social Media, Neural Network Newsletter Disclaimer & Disclosures Learn more about your ad choices. Visit megaphone.fm/adchoices
Chapter 1: What is the interplay between genes and behaviors?
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. My guest today is Dr. Melissa Alardo, professor of biomedical informatics at the University of Utah. Dr. Alardo is a world-renowned expert in human genetics and epigenetics.
She conducts pioneering studies on how our behavior and the environment can modify our gene expression. Today marks the first time on the Huberman Lab Podcast that we really explore human genetics, epigenetics, and how behavior shapes gene expression across generations.
We talk about the inheritance of physical traits like eye color, and we dive deep into fascinating mechanisms such as the mammalian dive reflex, a physiological reaction to breath holding in cold water that as Dr. Ilardo explains, can dramatically alter the physiology of your spleen to allow significant increases in red blood cell count and oxygen availability to your brain and body.
And by the way, the mammalian dive reflex can be activated outside of free diving, and you can even do it at home. We also explore how mate preference and selection in humans relates to the immune system. That is, if you were given a choice of many, many different mates, as most people are,
The mate you would select is the mate who has the immune system composition that is most different from yours. And you would know that on the basis of their smell and how attractive their smell is to you compared to the smell of other people. We also talk about how differences in external traits signal important variations in organ function, hormone levels, and even brain physiology.
Toward the end of our conversation, we discussed the current state and ethical considerations of gene editing in humans, something that's apt to be an increasingly important topic in the years to come because gene editing in humans is now possible and is happening.
As you'll soon learn, Dr. Alardo does incredible real-world experiments that reveal the remarkable interplay between genes and behavior. And she's an absolutely phenomenal teacher who makes complex genetic concepts accessible and practical.
The conversation is sure to change the way that you think about mate selection, your parents, their parents, and what you can do to optimize your physiology and health through behavioral practices that influence gene expression. 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, this episode does include sponsors. And now for my discussion with Dr. Melissa Allardo. Dr. Melissa Ilardo, welcome.
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Chapter 2: How does the mammalian dive reflex affect physiology?
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Rapid changes in gene expression in any organ could be at the surface of the body or it could be internally that are governed by some change in behavior.
Yeah, so I mean our genes are constantly changing how they're expressing based on what environmental stimulus is coming in. So we have these changes that happen on the order of minutes or hours or things like that. Then there's also changes that we're finding out are happening kind of over generations. So we now know that there can be epigenetic changes. So these are changes –
you know, little modifications to the genome that happen by things actually, molecules actually attaching to the genome and changing how genes express, that can be passed down. So this is really interesting from the perspective of things like trauma.
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Chapter 3: How can certain behaviors influence gene expression?
We don't totally know. I have my own personal theory, which actually relates to the fact that in a lot of places with cold water, so in Korea, in Patagonia, in Aboriginal Tasmania, it's all women diving. So I suspect that there's something unique about the physiology of women. um, that makes us better at diving in cold temperatures.
Where the men are afraid of the cold. I hear about a lot of guys that will, will spend dozens of hours picking apart deliberate cold exposure, uh, when it would take them a fraction of the amount of the time to get into the water. In my experience, this is not a controlled studies, uh, women are more tolerant of the cold, at least in terms of being willing to embrace it the first time around.
Interesting.
I have stories of, I won't say which countries, elite special forces, it wasn't the U.S., guys, in that case it was guys, being terrified of getting into cold water, but otherwise being willing to do very, very challenging and indeed very dangerous things. I know a woman who first cold plunged 10 minutes. She was just in there.
In my experience, women are more willing to get into the cold the first time. And then now there's a lot of debate online about cold tolerance in the two sexes, but I don't, the data aren't really solid there. So I Maybe the men are just afraid of going underwater.
It could be. These are some tough ladies, I will tell you that, even into old age. My colleague, Ju Young Lee at Seoul National University, she's been working with them for a very long time. And she did a study where she was trying to find retired haenyeo. And the only ones she could find were over 100 years old. Because they basically don't retire. They just die until they die, essentially.
So she had these two women who were about three feet tall who were retired henyo because those are the only ones she could find.
A hundred years old?
Mm-hmm.
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