Dr. Andrew Huberman, Ph.D. is a Professor of Neurobiology and Ophthalmology at Stanford University School of Medicine. His lab focuses on neural regeneration, neuroplasticity, and brain states such as stress, focus, fear, and optimal performance.
In this episode of Huberman Lab, Dr. Huberman describes the interplay between the brain and organs of the body and its influence on overall health, how factors in our body combine to influence mood, inflammation, recovery, and much more!
Host: Andrew Huberman (@hubermanlab)
Interoception (AKA sense of self): ability to sense what’s going on in our bodies
Crafting interoception is critical to set the stage for optimal performance and health
Interoception is often called the sixth sense and is as important as sleep
Vagus nerve: two-way system in our body that connects all of our organs to our brain, and our brain to all of our organs – if we can understand leveraging that system, we can use it to our advantage
The Vagus nerve is a communication system, relaying brain to body and body to brain
Nerves leave the brain and brain stem and send information to control bodily organs
Two fundamental features are needed to make the brain and body interact properly:
  • (1) Mechanical sensing relays information such as pressure and touch
  • (2) Chemical sensing relays information such as acidity, pathogen detection
For every organ in the body, both mechanical and chemical information is registered and sends signals to the brain for adjustment
We are sensing mechanical and chemical information about every organ in the body (except the brain which is a command center but has no sensation)
Organs have to tell the brain what’s going on – if you can regulate the mechanical and chemical environment of your body, the brain functions better
Lungs and diaphragm play a large role in breathing
The diaphragm is unique because it is composed of skeletal muscle so you can take control of your diaphragm and determine how you breathe
Breathing controls our heart rate by changing the way our brain thinks
Inhale: lungs expand, and the diaphragm moves down, and the heart gets bigger
When inhaling vigorously, the heart speeds up
Exhale: lungs deflate, te diaphragm moves up, and the heart gets smaller because it has less space
When exhaling, the heart gets physically bigger and flows at a slower rate
Breathing is a great example of interoception: if you exhale longer than inhale, you will slow down the heart rate
If you want to be calmer, emphasize exhales through physiological sigh: 2 inhales followed by a long exhale
If you want to be more alert, inhale longer than exhale
Box breathing: equal inhale and exhale duration
When you exhale all your air then hold your breath, you won’t be able to hold your breath long
When you inhale before holding your breath, you will be able to maintain longer
When carbon dioxide levels get to a certain level, neurons will cause you to breathe and inhale to bring in oxygen
You don’t want carbon dioxide levels to go too high or the brain will elicit a panic response
When you exhale, you offload carbon dioxide
Self-experiment to hold breath longer & achieve an alert but calm state: sit or lay down and breathe in deep (around 2 seconds) and exhale passively (around 1 second) – if you repeat 25-30 times, you will change the chemistry of your brain
  • In the first few reps, adrenaline starts to rush, and you feel alert
  • On the last breath, dump all air and hold breath for about 15-30 seconds
  • You will be able to hold your breath for a long time because you offloaded so much carbon dioxide
  • You will feel very alert but very calm
Once you understand the components of breathing, you can create breathwork practice that works best for you to achieve the desired outcome
The digestive system communicates to the brain about mechanical and chemical status to get information from the brain about how to respond
As you expand your gut and become full, a signal is sent by neurons and shut down the drive, and leave you literally unable to put more in your mouth and remove the desire
You can get better at registering a sense of fullness by paying attention and focusing on how much mechano-sensation (fullness and pressure) is in the gut, you can leverage (this can come in handy for fasting)
The details are debatable but it’s clear that having a period of fasting is helpful because it stimulates autophagy
Two main neurons in healthy eating: (1) one set of neurons that sense nutrients, telling the brain what’s in the gut; (2) another set of neurons that sense fatty acids (omega-3s), amino acids, sugar (sugar as a chemical, not sweet food)
  • These neurons don’t know the taste, they only know nutrient profile
If you have sugar cravings, replacing those foods with items that have high omega-3 or amino acid profiles can curb cravings
If you have sugar cravings, take 1 tsp of glutamine or mix with full-fat cream if the craving is extreme
Your gut needs to be more acidic than other organs of the body to function properly because bacteria thrive in alkaline conditions
Gastric juices are powerful modulators of brain health
“One of the best things you can do to have a healthy brain, well-functioning brain, and a healthy and well-functioning body is to maintain proper gut chemistry.” – Dr. Andrew Huberman
 By breathing through your nose most of the time, you will increase the microbiome in the nose
There are cytokines in the body that promote inflammation and reduce inflammation
The best way to adjust the microbiome is to ingest certain foods
In a recent study, a high fiber diet reduced diversity of gut microbiome diversity while 1-2 servings of ferments foods increased gut microbiome diversity:
  • Individuals given a high fiber diet experienced a reduced diversity of the gut microbiome
  • Individuals given a few servings of fermented food each day had high levels of anti-inflammatory biomarkers and improvements in gut microbiome diversity
  • We should all be ingesting fermented foods daily: starting with 2 servings per day, and maybe ramping up to 4 servings of fermented foods per day may offer significant benefit to gut microbiome diversity
  • Fermented foods far out-performed high fiber foods
  • A high fiber diet increases microbiota but limits diversity; adding fermented food to the diet increases microbiota diversity
  • Ingesting a high carbohydrate and high fiber diet might make people better at digesting carbohydrates
Benefits of consistent, daily consumption of fermented foods: inflammatory markers decrease, markers of auto-immune disruption decrease, and the chemistry of the gut adjusts in helpful ways
When the correct microbiota are present: cognition improves, ability to sleep improves, immunity is enhanced – even in the presence of autism or auto-immune system disease
Some data suggests glutamine can improve conditions of leaky gut
Controversial practice for people with auto-immune disorders: ingest 1-2 tablets of HCl tablets during meals to alter pH of the gut  
People who supplement with a lot of pro-biotics can experience some brain fog
The goal is not to create as much microbiota as possible, it’s to enhance microbiota diversity
Helpful tips to reduce nausea: ginger can cause a notable reduction in ginger (dose: 1-3g), peppermint, cannabis
Fever is an adaptive mechanism in our body
Fever relates to chemical sensing interoception: it’s an increase in body temperature, triggered by neurons in the brain which are triggered by the presence of foreign objects in the bloodstream
If you are overheating (from fever, exercise in a hot environment, so shade in sun):
  • Do not put a cool towel on the back of the neck! That cools the blood going to the brain and sends the wrong signal that things are cold and you need to warm up
  • Do cool the bottoms of the feet, the palms of the hands, and the forehead
You can train heightened levels of interoception to enhance the relationship to self, others, cognition, internal well-being
Most of the time the Vagus nerve is stimulatory, triggering the release of dopamine
Stress blocks the communication between gut and brain by shutting down the communication through the Vagus nerve
The Vagus nerve is responsible for emotion by pooling conditions of gut, heart, and breathing and uses that as a collection of information to send to the brain
Moods are created through changes in the heart’s response and breathing
Face, pupils, frowning/smiling are all a reflection of overall being, gut, heart, breathing, and state of body
Our heart rate and breathing mimic the experience of people we care about – humans can register the internal state of other humans at a distance
Learn to sense your heartbeat: if you sit calmly and direct awareness toward heartbeat (similar to meditation) you will turn up interoceptive awareness and be more connected to gut instincts – take a minute or two and try to count heartbeats