Preserving Brain Health

Unlock the secrets to a sharper mind with Dr. Hillary Lin as she explores cutting-edge strategies for brain health. From exercise and nutrition to cogniti…

Published September 19, 2024The Longevity Show

Cognitive reserve is a mental savings account you deposit into across a lifetime, and Dr. Lin's argument is that most people are making the wrong deposits. The instinct is to reach for Sudoku and brain-training apps — and her position is that this mostly makes you good at Sudoku. Real cognitive resilience comes from real activity, for the same reason she prefers nutrients from food over pills: the brain absorbs from context better than it absorbs from isolated tasks.

The organising idea is that the brain is not a separate system to be trained separately. Brain fog is a signal that something is happening in the body — most often inflammation, which is why she has seen dozens of patients on GLP-1 agonists report unexpectedly clearer thinking alongside weight loss, a phenomenon she attributes to the anti-inflammatory effect while noting it is studied mostly in animal models rather than humans. The interventions that work are consequently whole-body: aerobic and resistance exercise, brain-healthy dietary patterns, sleep, social engagement, and the specific supplements with mechanisms behind them.

The timing argument is the one that should change behaviour. Dementia and mild cognitive impairment are far easier to prevent than reverse — reversal being, on current evidence, either impossible or exceedingly difficult — which pushes the intervention window back into your thirties and forties rather than your sixties. The episode closes with ketamine for treatment-resistant depression, where Dr. Lin discloses deep personal experience with the drug and is unusually explicit about who it is not for.

Before you watch

Brain fog is a symptom of the body, not the mind. Dr. Lin's framing is that the brain acts as a detector — when it senses inflammation or toxins it cannot respond as quickly, producing the sluggish, almost stoned quality people describe, with impaired recall and harder learning. That reframing is why she treats brain health as a whole-body problem, and it is the mechanism she credits for a pattern she has now seen in dozens of patients: people starting GLP-1 agonists reporting that their thinking cleared, which she attributes to the drugs' anti-inflammatory effects while noting this is studied mainly in animal models so far.
Different exercise modalities train the brain differently, and resistance training earns its place through an unexpected mechanism. Aerobic work raises BDNF, improves blood flow carrying oxygen and nutrients, and reduces inflammation, with high-intensity intervals having the largest effect. The theory behind resistance training is that learning to squat or deadlift properly requires your brain to build and extend neural pathways to the muscles — the movement is genuinely complex to coordinate. Balance-based work like yoga, tai chi and dancing is computationally demanding for the same reason.
Her aside on the cerebellum is one of the more interesting things in the episode. Alcohol damages it, which is why heavy long-term drinkers can remain unsteady when sober — and the same structure governs your perception of the passage of time. Dr. Lin's own example is that mornings feel like they pass quickly because she is operating slowly, while late at night she can fit far more into a single minute. Time genuinely is relative to your neurological state.
On cognitive training she is directly skeptical of the products built to sell it. Doing Sudoku extensively makes you good at Sudoku — it does not obviously transfer to building a financial model, giving a talk, or remembering people's names. Her analogy is supplements versus food: the puzzle app is the convenient isolated version, while real-life activity is the whole-food equivalent your brain is better equipped to absorb from. Her recommendation is 15 minutes a day of something genuinely challenging, varied across domains, and ideally done with other people.
She practises what she recommends in an unusual way: she has completed more than 200 escape rooms, with over 230 recorded and a suspicion the real number is higher. Her reasoning is that she dislikes phone and computer puzzles precisely because they are isolated from context, whereas escape rooms are whole-body puzzling done with other people. She extends the same logic to travel, framing it as whole-body learning — new places, people and foods — rather than as time off.
The dietary evidence converges rather than competes. Mediterranean, DASH and MIND diets all show associations with better cognitive health and lower neurodegenerative risk, and they share the same core: plants, whole grains, nuts, lean proteins, and limited saturated fat and sugar. Dr. Lin is notably unbothered about red meat, pointing out a palm-sized portion delivers 20 to 30 g of protein and up to 40 depending on thickness, with leaner cuts and game meat like venison being her preference. On omega-3s she is blunt that plant sources are impractical — you would need them to be most of your diet — so fish, or algae-based supplements for vegans, with roughly a serving of fish a day sufficient for most people.
Breath work is something she openly changed her mind about, having previously considered it woo. Slow diaphragmatic breathing has been shown to enhance autonomic regulation, improve cognitive performance and reduce stress. The technical detail worth knowing is that the exhalation does the work: box breathing at four counts in, hold, four out is fine, but inhaling more quickly, holding briefly and then exhaling over five to ten counts through pursed lips is more effective at slowing the heart. This raises heart rate variability and lowers cortisol, and she notes a distinct shift around the twelve-minute mark.
Creatine dosing for the brain is double the dose people use for muscle, and the reason is pharmacokinetic. Creatine enters muscle readily but crosses into the brain far less easily, so while 5 g daily suffices for muscle performance, cognitive benefit requires more — Dr. Lin suggests 5 g twice daily, or three times for larger people who tolerate it without bloating or GI symptoms. Creatine monohydrate is the purest form and generally the best tolerated.
Creatine is most valuable exactly when you are most depleted. It enhances brain bioenergetics and provides neuroprotection specifically under metabolic stress — sleep deprivation, hypoxia, shift work, jet lag — with studies showing improved cognitive performance and memory alongside protection against excitotoxicity and oxidative stress. Dr. Lin discloses using extra creatine while adjusting her sleep ahead of travel to Asia, complicated by automatic blinds that kept opening too early.
The creatine lab caveat matters practically: creatine raises creatinine, the marker most panels use to assess kidney function, which can prompt a doctor to suspect acute kidney injury. Her advice is to tell them you are supplementing and ask for cystatin C instead, which assesses kidney function without being distorted by creatine use.
On ketamine she discloses deep personal experience with the drug and then spends most of the section on limits. It is for people with deep depression or PTSD who have the support of loved ones and a trusted physician — not for most people, and not recreationally, where it is psychologically addicting because it makes you feel better. She does not endorse indefinite prescribing. The risks she names are abuse potential and cystitis, a bladder inflammation that feels like a UTI that will not resolve, plus the setting risk that at high doses it is an anaesthetic. The protocol matters as much as the molecule: preparation with journaling and a therapist, a session done eyes closed with music in a meditative state rather than walking around hallucinating, then integration with a support person afterward. She also notes it is not the only fast-acting option, pointing to transcranial magnetic stimulation and stellate ganglion blocks.

Chapters

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Summary and Actionable Steps for Brain Health

Questions

Do brain training apps actually work?

Dr. Lin's answer is that they work narrowly — you get better at the specific task. Extensive Sudoku makes you good at Sudoku, and it does not obviously transfer to building a financial model, speaking in front of an audience, or remembering people's names. Her analogy is supplements versus whole food: the app is the convenient isolated version, while real-life activity is what your brain is actually equipped to learn from. Her recommendation is 15 minutes daily of something genuinely challenging, varied across different domains rather than repeating one, and preferably done with other people, since most people learn better socially. Travel counts, which she frames as whole-body learning rather than time off.

How much creatine should I take for brain benefits?

About double the muscle dose, because creatine crosses into the brain far less readily than into muscle. For muscle performance 5 g daily is sufficient; for cognitive benefit Dr. Lin suggests 5 g twice a day, with a third dose reasonable for larger people who tolerate it. Creatine monohydrate is the purest form and generally best tolerated, though some people report bloating or GI symptoms. It is most useful under metabolic stress specifically — sleep deprivation, shift work, jet lag, hypoxia — where studies show improved cognitive performance and memory alongside neuroprotection against excitotoxicity and oxidative stress. One practical warning: creatine raises creatinine and can make kidney function look abnormal, so tell your doctor and ask for cystatin C instead.

Why does GLP-1 medication seem to clear brain fog?

Dr. Lin has observed this in dozens of patients — people starting semaglutide or tirzepatide reporting that beyond the weight change, their thinking became clearer. The leading explanation is the anti-inflammatory effect of these drugs, and she is careful to note this has been studied mostly in mouse and animal models rather than fully in humans, though there is no strong reason to expect the anti-inflammatory mechanism to differ. Her broader framing is what makes this coherent: brain fog is a signal that the brain is detecting inflammation elsewhere in the body and responding sluggishly, so anything that lowers systemic inflammation can lift it.

What kind of breathing actually reduces stress?

The exhalation is what matters, which is the detail most instructions omit. Dr. Lin — who admits she previously dismissed breath work as woo — describes slow diaphragmatic breathing as improving autonomic regulation, cognitive performance and stress. Box breathing at four counts in, four holding and four out works, but she finds it more effective to inhale relatively quickly, hold briefly, and then exhale slowly over five to ten counts through pursed lips or teeth. That deliberately slows the heart, raises heart rate variability and lowers cortisol. Five to ten minutes is a reasonable starting point, and she notes a distinct shift around twelve minutes if you can extend it.

When should I start protecting my brain from dementia?

Considerably earlier than most people assume — Dr. Lin points to the thirties and forties, and certainly the fifties and sixties. The reasoning is asymmetry: extensive research into dementia has established that prevention is far more achievable than reversal, and the working assumption is that once mild cognitive impairment has set in, reversing it is either impossible or exceedingly difficult. That means the useful window is well before any symptoms appear. What goes into it is unglamorous — regular exercise, a Mediterranean-style dietary pattern, consistent sleep, genuine social engagement, and supplements with real mechanisms behind them like omega-3s, creatine and magnesium.

Who is ketamine therapy actually appropriate for?

A narrow group, and Dr. Lin — who discloses substantial personal experience with the drug — spends most of her time on the boundaries. It is for people with deep depression or PTSD, particularly where SSRIs, bupropion and antipsychotics have failed, and who have both the support of loved ones and a trusted physician. She does not endorse recreational use, noting it is psychologically addicting because it makes people feel better, and she does not support indefinite prescribing. Risks include abuse potential and cystitis — bladder inflammation that presents like a UTI that will not clear — plus setting risk, since at high doses it is an anaesthetic. The structure matters too: preparation with a therapist beforehand, a session conducted eyes closed with music in a meditative state, then integration afterward. She notes TMS and stellate ganglion blocks as other fast-acting options.

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