The longevity industry has a simple story about the brain: it declines, the decline is mostly fixed, and the best you can do is slow it with the right supplements and the right wearables. Tommy Wood spends a lot of his time arguing the opposite. The brain adapts across almost the whole of a life, the levers that matter are unglamorous, and the obsessive measuring the industry sells can actually make people perform worse.

Wood is a physician and neuroscientist who studies brain health and metabolism, advises Formula One teams on driver performance, and competes, improbably for a man who spends his days thinking about cognition, in strongman. He co-hosts the Better Brain Fitness podcast with the neurologist Josh Turknett and is the author of The Stimulated Mind. He is medically trained and has worked as a doctor, though he no longer practises clinically.

What makes him intriguing is the consistency of the inversion. On dementia, on concussion, on cognitive enhancement, on sleep, he keeps arriving at the same place: the body is more robust than we are told, the evidence is thinner than the marketing, and the most useful interventions are the boring ones.

Let’s start broad. What actually drives brain health?

It coalesces around some core factors, and I think about it in three buckets. The most important driver of cognitive function is how we use our brain. It’s just like exercise — the brain responds to a challenge the same way the body responds to physical training. Are we continuing to challenge it, develop the skills we want it to be good at, across the whole lifespan? That’s bucket one. Bucket two is supply: getting oxygen and glucose to the brain, which means good cardiovascular and cardiometabolic health, and the nutrients you use to build new connections — omega-3s, B vitamins, iron, vitamin D. Bucket three is support: giving time for adaptation, which happens during sleep, and avoiding the things that inhibit it — excessive alcohol, smoking, chronic inflammation, even dental disease and air pollution.

There’s no agreed definition of concussion. Why does that matter?

We don’t really know what kind of impact, or where, is enough to disturb the health of the brain in a way that isn’t currently detectable but could have long-term implications. We’re now appreciating things like CTE, which you can’t formally diagnose until that person’s brain is under a microscope after they’ve passed away. I work with a great neurosurgeon, and when I first met him he asked, have you ever had a concussion? I said no. And he said, well, how do you know? Because by his definition I could have had several and never know about it. That’s where the grey area is.

On managing a head injury:

So if someone’s had a serious head injury, what actually matters?

In the first 72 hours, the most important things are regulating blood sugar, getting enough sleep, and regulating temperature. On temperature — there’s a big move in sports like international rugby to actively cool the brain after an impact, with cooling caps. That’s been tested in dozens of trials costing billions, and active cooling doesn’t really work for any brain injury except in newborns. The thing that matters is avoiding a fever, because as temperature rises you increase the brain’s metabolic demand at exactly the point its energy production is impaired. External head cooling doesn’t make sense, because you’re still sending hot blood up the carotid arteries from the rest of the body. For recovery, light aerobic exercise as soon as you can tolerate it — just below the intensity that triggers symptoms — is one of the best things going.

You did your PhD work near this. How would you sharpen up cognitively for a big performance?

Number one, two and three is adequate sleep. By then you hope you’ve done the preparation and you’re just executing on it. Beyond that it depends on the task, because of the Yerkes-Dodson arousal curve — there’s an optimal level of arousal for any given task. A sprinter needs to be highly aroused; an archer needs to be calm, which is why they used to use beta blockers. I do some work in Formula One, and we’ve seen that if you amp a driver up, they’re faster off the line but worse at the complex tasks — cornering, listening to the pit wall. So one person’s enhancement is another’s hindrance. If you need more arousal, caffeine, creatine, tyrosine, taurine can help, especially when sleep-deprived. If you’re already anxious, you need the opposite — breathwork, meditation.

Walk us through a normal day…

I work back from when I wake up. The dogs get up at six, so if I want nine hours of sleep opportunity I’m in bed at nine. I don’t eat right before bed, so dinner’s around six or seven, then a wind-down — lights down, blue-light glasses, which at this point are almost Pavlovian. In the morning, coffee, and I don’t worry about waiting to have it — if you think it helps you, it probably will. I start work at seven and do my focused work between seven and ten, when I’m sharpest, then save the afternoon for emails and meetings. I knock off about three, train six days a week, and cook almost all our food at home — high protein, low refined carbohydrate. Training is two days of low-level aerobic work and four days lifting, currently built around a strongman competition.

And if you’ve had a bad night’s sleep?

The most important thing is probably not to worry about it. There are very nice studies showing that if you think you slept poorly — even if you slept well — you’ll perform cognitively worse. If you normally sleep well, exercise and eat well, you can tolerate the occasional bad night just fine. What I get concerned about is the pursuit of continued optimisation, where you create a scenario in which, when things aren’t optimal, you actually perform worse, because you think you didn’t get everything you needed. All these behaviours are building resilience and headroom. We talk about optimising and it creates this perception that the human body is frail. It’s not. It’s incredibly resilient and adaptable.

What about the longevity supplements such as NMN, NR?

The NAD story is interesting — these are taken to top up cellular NAD, which declines with age. What’s more interesting is why NAD declines: chronic stress and inflammation send the kynurenine pathway down a different road. So the things that protect NAD are the lifestyle factors we already talked about. I don’t think the evidence is good enough yet that I’d take NMN or NR. What I do find interesting is plant polyphenols — berry anthocyanins, particularly wild blueberries, have nice evidence for cognitive function; I’d eat a cup or two a day after a concussion. The reason I like that is it’s perfectly safe and super low risk. At the end of the day, the worst thing that happened was you had some nice blueberries. You’ve got to eat something.

And high protein, can you put the kidney-damage worry to bed?

First, as a physician I’m not really qualified to talk about nutrition, because we’re not taught any of it in medical school. But there’s basically no evidence that high-protein diets are bad for you — most of the studies suggesting it are poorly done. There are studies of people eating more than four grams per kilo per day with no detectable negative effects. Most of the benefit comes at about 1.2 grams per kilo, levelling off around 1.5 to 1.6, a bit higher for athletes or people in a deficit. The standard recommendation is 0.8; I’d put the floor at 1.2, which is what most people would call high protein. And it matters more as you get older, because of anabolic resistance — you need more protein to hold on to muscle.

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