Using Your Nervous System to Enhance Your Immune System

High-Level Overview

In this solo episode, Andrew Huberman explores how the nervous system and immune system talk to each other, and how that connection can be used to prevent illness and recover faster. He points out that 10 to 20 years ago the idea that the mind could control the immune system would have been laughed out of academic conferences, but there are now dozens if not hundreds of quality peer-reviewed studies on it, including a new Nature paper on how acupuncture can reduce inflammation. After a clear primer on the immune system's three layers of defense, he explains "sickness behavior", the set of changes in mood, appetite and energy that come with illness, and how signals from the body reach the brain. He then flips the equation to what we can do with the nervous system to boost immune function: nasal breathing, fermented foods, sleep with the feet elevated, heat exposure, a specific breathing protocol, mindset and dopamine, and supplements like spirulina for congestion.

The tone is educational and enthusiastic, with Huberman promising "healing with the mind in a completely non-mystical non-abstract sense" and grounding each tool in a specific study or mechanism. The episode moves from basic immunology to the brain pathways of sickness and then into a series of practical protocols, closing with excitement about ancient practices converging with modern mechanistic science.

The Discussion Explores:

• The immune system's three layers: barriers, the fast innate response, and the adaptive response that makes antibodies
• Protecting the mucosal barrier with nasal breathing, not touching your eyes, and fermented foods
• Sickness behavior as a motivated state, and its striking overlap with major depression
• How the vagus nerve and blood-borne cytokines signal illness to the brain, producing fever, light sensitivity and sleepiness
• Sleep, serotonin and the glymphatic system, including elevating the feet
• Sauna and heat, and why adrenaline from a breathing protocol can reduce inflammation
• Mindset, dopamine and hope as real biological levers on healing
• Spirulina for congestion, and electroacupuncture activating an anti-inflammatory pathway

Deep Dive into Main Ideas

The Foundations, Then Beyond Them

Huberman starts by tipping his hat to the generic advice for immune health that deserves respect: consistent, high-quality sleep most nights, sunlight in the eyes in the morning and evening while avoiding bright light at night, about 150 to 180 minutes of zone 2 cardio per week, good nutrition that avoids processed foods, social connection and hydration. But many people still get sick too often or heal slowly, so the episode focuses on additional ways to leverage the nervous system for more robust immune function.

Immune System 101: Three Layers of Defense

The first layer is a physical barrier: the skin plus the openings to the outside world (eyes, ears, nostrils and mouth) and the mucus-lined tube running through the digestive system. Mucus acts as a trap and filter for bacteria and viruses and is constantly being turned over. The second layer is the innate immune system, a fast, general response. White blood cells such as neutrophils, macrophages and natural killer cells rush to the site of invasion to surround and engulf invaders, a bit like putting them in a body bag, which is what pus is. Complement proteins in the blood tag invaders with an "eat me signal, and damaged or infected cells release help me" signals called cytokines, including interleukin 1, interleukin 6 and tumor necrosis factor alpha, which are the markers usually measured when people talk about inflammation. Not all interleukins are inflammatory; interleukin 10 is anti-inflammatory, and it comes up again later.

The third layer is the adaptive immune system, which makes an imprint of an invader's shape and creates specific antibodies against it, forming a memory so the body can respond immediately next time. These cells arise from hematopoietic stem cells in the bone marrow. Huberman explains that IgM antibodies appear first and indicate a fairly recent infection, while IgG antibodies come later and are more stable.

Protecting the Barrier: Nose, Eyes and Gut

A key way to keep defenses tuned is to maintain a healthy microbiome along every mucosal surface; there are distinct microbiomes in the eyes, mouth, nose, gut, urethra and vagina. Huberman offers three practical steps. First, breathe through your nose whenever you're not eating, speaking or exercising hard. The nasal microbiome is good at scrubbing bacteria and preventing infections, and he cites a Cell Reports paper on specific nasal microbiota that fight infection. He recommends the book Jaws by his Stanford colleagues Sandra Kahn and Paul Ehrlich on the costs of mouth breathing, and notes that breathing through the nose can gradually help open narrow sinuses.

Second, heed the old advice not to touch your eyes after touching people or surfaces, since the eyes are a primary entry point. He mentions that most people unconsciously wipe another person's chemicals onto their face within about 30 seconds of meeting them, and that the "sleep in your eyes each morning is dead bacteria from a nighttime fight: you're wiping away the casualties of a battle that you fought at night." (He then catches himself wiping his own eye mid-sentence.) Third, eat two to four servings a day of low-sugar fermented foods, such as sauerkraut, kimchi, natto or pickles. He cites work from Justin Sonnenberg's lab at Stanford, published in Cell, showing this reduces inflammatory cytokines. He explains that this doesn't leave cells more vulnerable; with a healthier gut microbiome, fewer cells are being infected, so fewer are crying out for help.

Sickness Behavior: Your Brain's Response to Illness

Huberman describes sickness behavior, a suite of changes that bridges the immune and nervous systems: lethargy, reduced grooming, loss of appetite and loss of libido. He stresses that "sickness behavior is actually a motivated state" designed to accomplish things. Loss of appetite may help prevent the spread of infection through vomiting and diarrhea, conserve resources for repair, and, according to one theory, reduce iron intake, since many bacteria thrive when blood iron is high. (He gives typical iron intake recommendations of about 8 milligrams a day for men and 18 to 27 for women, and cautions against extreme iron-deprivation diets.) Resting slows blood circulation, which appears to let the lymphatic system ramp up.

People also split into two roughly equal groups when sick: about half want to be cared for, and half want to be left alone. He recalls his late bulldog Costello hiding behind the house whenever he was ill. Strikingly, sickness behavior closely mirrors major depression, including lethargy, loss of appetite and libido, and elevated interleukin 6 and TNF alpha. This overlap, he says, suggests interventions that help one might help the other, and it shows the constant interaction between brain and immune system.

How the Body Tells the Brain It's Sick

There are two pathways. The fast route is the vagus nerve, the tenth cranial nerve, which connects organs such as the lungs, heart and gut to the brain. Huberman notes that the popular idea that the vagus simply calms us down is more or less a myth, since vagal stimulation often increases alertness. When infection triggers inflammation, the vagus signals the hypothalamus, where neurons in the preoptic area raise body temperature. He explains that "a fever actually has a functional role" because many viruses and bacteria don't survive well at higher temperatures, so lowering a fever with drugs may make you comfortable but limits the body's response, though fevers shouldn't go too high because they can kill brain cells.

Illness also produces photophobia through a pathway from the eye to the anterior thalamus and up to the meninges, identified by Clifford Saper at Harvard, creating headaches in response to light and driving people into quiet, dark places. A hypothalamic area above the optic chiasm promotes sleepiness even during the day. The slow pathway is humoral, carried by the blood: over hours or days, cytokines build up and enter the brain through the choroid plexus in the ventricles, impairing memory and cognition, which is why deep into an illness you can't read or even watch a movie.

Sleep, Serotonin and the Glymphatic System

When the first signs of illness appear, the usual advice is to hydrate and sleep. Huberman explains that sleep during early infection seems to involve elevated serotonin from the raphe nucleus, which may enhance immune function, and there are emerging studies on whether serotonin precursors like 5-HTP or tryptophan-rich foods (such as turkey and some complex carbohydrates) help. More clearly established, the brain's glymphatic system, a plumbing system that clears out debris, is much more active during deep sleep and early infection, and it matters for recovery from infection and possibly head injury.

His practical tip: elevate your heels by about 12 degrees while sleeping, for instance with a rolled pillow or two under the feet, which seems to increase glymphatic clearance. The glymphatic system is also active during deep relaxation, so he suggests using a self-hypnosis or sleep script from Reveri, the free app developed by his Stanford colleague David Spiegel, with the feet elevated. He doesn't generally recommend 5-HTP for sleep because it can disrupt normal sleep architecture, but at the early stage of an illness, after checking with a doctor, the typical protocol is 300 to 500 milligrams taken 30 to 60 minutes before bed. He points listeners to a review titled The Glymphatic System: A Beginner's Guide, and a paper linking glymphatic dysfunction to iron deposition in the aging brain.

Heat: Upgrading the Hot Shower

The advice to take a hot shower when coming down with something holds up. Huberman cites a study on a single Finnish sauna session in athletes and non-athletes: just one 15-minute session improved white blood cell profiles and adjusted cortisol in ways that help fight infection. If you want more, alternating about 15 minutes of heat with 5 to 10 minutes of cooling seems beneficial, because it forces the hypothalamus to send repeated pulses of these signals. No sauna? A very hot bath or shower, or a steam-filled bathroom, is a reasonable substitute. The critical caution: don't use a sauna if you already have a fever, since it could raise your temperature to dangerous levels: "please don't kill your neurons." He also muses on the saying "feed a fever, starve a cold," noting that eating raises body temperature, while the logic behind starving a cold remains a mystery to him.

Breathing to Release Adrenaline and Reduce Inflammation

The centerpiece is a PNAS study by Kox and Pickkers. Volunteers were injected with an E. coli endotoxin, which normally produces fever, vomiting and flu-like misery. Compared with controls who did basic meditation, people who practiced cyclic hyperventilation with breath holds, similar to Wim Hof or tummo breathing, had higher levels of the anti-inflammatory cytokine IL-10, lower levels of TNF alpha, IL-6 and IL-8, and fewer flu-like symptoms. The effect was driven by a large increase in epinephrine (adrenaline). Blood pH rose from about 7.4 to 7.6, though the authors attribute the effect to adrenaline rather than pH. (In passing, Huberman says "don't waste your money on drinking alkaline water.")

He stresses that this isn't blocking the immune response but arguably enhancing it, and that it explains a familiar experience: pushing through exams or caretaking without getting sick, then falling ill the moment you stop, as adrenaline recedes. The protocol is about 25 to 30 deep breaths in and out, then exhaling fully and holding with lungs empty for roughly 15 to 60 seconds until the urge to breathe, repeated for three rounds. Both the hyperventilation and the breath hold matter. He has used it for more than four years whenever he feels the early signs of a bug. Safety notes: never do this near water or while driving, and don't force the breath hold.

Mindset, Dopamine and Hope

In the same study, epinephrine rose strongly, norepinephrine rose modestly and dopamine dropped somewhat, which leads Huberman to work from Asya Rolls's lab in Israel showing that motivational state and mindset affect immune function. Negative thoughts can make us sick: a Science paper by Kataoka identified a cortico-limbic-hypothalamic pathway through which psychological stress creates fever, and blocking it prevented psychogenic fever. On the positive side, Rolls's lab found that activating the mesolimbic dopamine reward pathway, which relates to a sense of hope and the future, could reduce tumor size and accelerate healing.

Huberman mentions that some people explore dopamine precursors like L-tyrosine (500 to 750 milligrams) or Mucuna pruriens, which contains L-dopa, while emphasizing that they can cause crashes, aren't for people with bipolar disorder, mania or schizophrenia, and should be discussed with a doctor. Cold water immersion, uncomfortably cold but tolerable for 3 to 10 minutes, can double or more baseline dopamine and epinephrine for hours, which may explain the appeal of hot-cold contrast therapy. The common thread is that the catecholamines (dopamine, epinephrine and norepinephrine) are the bridge through which the nervous system calls up the immune system.

Easing Symptoms With Spirulina

Once symptoms arrive, over-the-counter decongestants that work through the epinephrine system can dehydrate you and disrupt sleep, especially REM sleep, which depends on low adrenaline. Huberman highlights spirulina, a type of algae that once seemed like a 1970s health-food fad, as an alternative for rhinitis, meaning inflammation of the nasal passages. Two randomized, double-blind human studies (with 129 and 65 subjects) found about 2 grams a day reduced nasal obstruction and itching, improved smell and sleep, and lowered inflammatory cytokines, sometimes after taking it for a while. Mechanistically, spirulina inhibits histamine-releasing mast cells, the same cells behind hives and seasonal allergies. He cautions that people with the genetic disorder PKU should avoid it, and notes he has no relationship with any spirulina company.

Acupuncture's Anti-Inflammatory Pathway

Finally, Huberman describes the Nature paper from Qiufu Ma's lab at Harvard Medical School on the neuroanatomical basis of electroacupuncture. Stimulating the abdomen increased inflammation, while stimulating the hind limbs activated neurons whose endings sit in the deep fascia, the dense sheath around muscles. Those neurons connect through the spinal cord to the medulla, which signals the adrenal glands to release epinephrine, norepinephrine and dopamine, reducing inflammation even after an injection of lipopolysaccharide. He is delighted that ancient practices like acupuncture and breathwork are converging on the same mechanism modern science is uncovering, which validates them, may someday affect insurance coverage, and could lead to new, more effective protocols people can do at home. He also notes the NIH now funds complementary health research through NCCIH.

Conclusion

Huberman's core message is that the immune system doesn't work in isolation: the brain and body are constantly signaling each other, through the vagus nerve, blood-borne cytokines and catecholamines like adrenaline and dopamine. Sickness behavior is the body's way of making us rest, heat up and withdraw, and it overlaps strikingly with depression. Beyond sleep, sunlight, exercise and good nutrition, you can support your defenses by breathing through your nose, keeping your hands away from your eyes, eating fermented foods, sleeping with your feet elevated, using heat early (but not with a fever), and trying cyclic hyperventilation with breath holds at the first sign of illness. A hopeful mindset has real biological effects, and tools like spirulina and electroacupuncture now have mechanisms behind them, offering a genuinely non-mystical way to help the mind support healing.

This is a summary of "Using Your Nervous System to Enhance Your Immune System" from Huberman Lab, giving you the GIST so you can decide if you want the REST. Listen to the full episode.