Andrew Huberman — Professor of neurobiology and ophthalmology at Stanford School of Medicine and host of the Huberman Lab Podcast, known for translating neuroscience into actionable health protocols.
The gist
This is a solo Huberman Lab episode on interoception, the brain's sensing of its own internal landscape such as heartbeat, breathing, and gut state. Huberman explains how mechanical and chemical signals travel between organs and the brain via the vagus nerve, and how breathing patterns directly speed up or slow down heart rate. He covers gut fullness and nutrient-sensing neurons, gut acidity and the microbiome, leaky gut, vomiting, and fever as chemical-sensing reflexes. He highlights new research that fermented foods beat high-fiber diets for microbiome diversity, and closes with tools to strengthen interoceptive awareness by sensing one's heartbeat.
Big reveals
- A Stanford study (Sonnenberg lab, in Cell) found a high-fiber diet reduced gut microbiome diversity while fermented foods increased anti-inflammatory benefits.
- Inhales speed the heart up and exhales slow it down because diaphragm movement changes heart volume and blood flow, registered by the brain.
- Fermented foods far outperformed the high-fiber diet for reducing inflammation, contradicting what most people were taught about fiber.
- Your brain sits behind the blood-brain barrier and sensing neurons trigger vomiting when blood is too acidic or contains pathogens.
- Cooling the back of the neck during overheating is wrong; it cools blood to the brain and makes the brain crank temperature higher.
- The vagus nerve is mostly stimulatory, not calming; it is a communication and motor system, not just a relaxation switch.
- Huberman flatly states psychedelics do not cause neurogenesis despite recent news claims, only changes in brain plasticity.
Things worth remembering
- The physiological sigh, two inhales followed by a long exhale, is the fastest way to calm down by slowing heart rate.
- Doing 25-30 deep breaths then exhaling and holding lets you hold your breath far longer by blowing off carbon dioxide.
- The brain itself has no pain or pressure receptors, which is why brain surgery can be done without anesthesia on brain tissue.
- GLP1R neurons sense intestinal stretch and GPR65 neurons detect nutrients, signaling the brain to eat more or stop.
- Sugar cravings can be reduced by ingesting glutamine, sometimes mixed with full-fat cream, because gut neurons sense nutrients not taste.
- You have a microbiome in your nose, and nasal breathing instead of mouth breathing improves it and immune defense.
- Ginger (one to three grams) is backed by research to reduce nausea, as can peppermint and cannabis.
- When you know someone well, your heart rate and breathing start to unconsciously mirror theirs, even at a distance.
- Interoceptive awareness can be strengthened quickly just by sitting and trying to sense your own heartbeat.
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Glutamine
“for many people, the solution to sugar cravings is to ingest a small amount, maybe a teaspoon or so of an amino acid called glutamine” — Andrew Huberman 00:57:14Find it on Amazon