Podbit · The Diary Of A CEO with Steven Bartlett
Vitamin D activates a gene that makes the enzyme that produces acetylcholine — the neurotransmitter the brainstem needs to enter REM sleep. When vitamin D levels drop, the brain loses the chemical instructions for sleep entirely.
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At 38:40 · chapter starts 24:56
Between September and December 2009, Dr. Gominak tested vitamin D and B12 levels in around 500 patients — 'completely naive' to what she would find. Every single one was low. Two CPAP patients returned and independently reported the same thing: a year of CPAP hadn't cleared their headaches, but a month of vitamin D supplementation (from a note she had sent them) had resolved their sleep and headaches simultaneously. She turned to PubMed. In 2009, searching 'vitamin D and sleep' returned zero results. Searching 'vitamin D in the brain' led her to Walter Stumpf — a researcher who had published since 1982 showing vitamin D receptors inside the exact brainstem nuclei that paralyse the body during REM sleep and set the circadian clock. Stumpf had also proposed vitamin D as the 'hibernation hormone,' orchestrating the body's seasonal adaptation. She called Stumpf directly, and he confirmed no one had connected his vitamin D receptor findings to sleep. From 2010 she began giving patients vitamin D. She describes the political obstacle: the Endocrine Society's 2004 report acknowledged that clinical vitamin D studies had been done wrong (fixed doses, no blood-level monitoring), and then — instead of calling for better studies — recommended that doctors neither test vitamin D levels nor make supplementation recommendations, effectively killing clinical inquiry.
Every neurological patient Dr. Gominak tested showed abnormal sleep — regardless of their diagnosis. If sleep is how the body repairs everything every night, then abnormal sleep isn't a symptom of disease — it's the cause.
Researcher Walter Stumpf published articles in 1982 showing vitamin D receptors exist in the brainstem nuclei that control paralysis during REM sleep and set the body's sleep-wake clock.
Spike your cortisol in the first 1–3 hours of your day — with sunlight, hydration, exercise, or caffeine — and you set up elevated mood, focus, and stress resilience for the rest of the day. Miss that spike and you get a flat cortisol curve: brain fog, poor learning, and bad sleep. The bookend is equally important: dim lights, no caffeine, and wind down the final hour.
Bottom-up impulses — just eat the cookie, keep scrolling — are driven by deep brain structures. Top-down prefrontal control is the thing that lets you wait, learn, and grow. Every small act of choosing the harder thing, from picking up trash to doing the workout you dread, greases that top-down circuit — and it transfers to everything else.
A Washington University in St. Louis study found that the attention-improvement effects of Ritalin are effectively equal to a great night's sleep. Stimulants also stunt growth and reduce sleep quality. The new direction is combining lower medication doses with genuinely better sleep — not replacing sleep with pharmacology.
Two big inhales through the nose, then a full exhale to empty — that's the physiological sigh. It fires a specific vagal pathway to slow your heart rate, offload CO2, and tip the autonomic nervous system toward calm instantly. Doing just 10 deliberate exhales throughout the day measurably elevates HRV by nighttime.
Presence isn't a state you fall into — it's something you actively produce by anchoring perception to the immediate environment. Ask 2–3 trivially specific questions about your surroundings (how many cans, what does it smell like) to pull your brain out of past/future mode. Then deliberately choose what to think or say next. That's it.
Acknowledge the thing, feel all of it, uncouple the emotion from the memory, then transmute the experience into something meaningful. Most people stall at step 2 — feeling the feelings — and never reach uncoupling. An entire generation is stuck there, confusing emotional processing for healing. Moving through all four is the actual path out.
Nicotine creates a uniquely alert-and-calm state ideal for learning — but only at low doses used occasionally. If you're using 3–6 mg pouches multiple times a day, you're not getting a cognitive enhancement, you're just rescuing yourself from withdrawal. For a genuine performance effect, use it once or twice per week at most.
Two injections of BPC-157 (100–200 mcg) eliminated shoulder pain Huberman couldn't shift for months. The peptide pinealon gave him 2.5–3 hours of REM sleep inside 6 hours — an effect that persisted into subsequent nights and scaled down to just once per week. Neither is in the book because the human data aren't there yet, but the animal evidence is strong.
Long, slow cardio builds capillary networks and mitochondrial richness; high-intensity intervals push VO2 max. You don't need huge volumes of either. Huberman's protocol: one 45–60 minute long slow session, one near-maximal effort HIIT session (Airdyne 20-on/10-off for 6–8 rounds), and one medium 30-minute effort per week. That's the complete cardio picture.
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