A (13:24)
Exactly, yeah. The way I think about it is very similar to a stimulus recovery adaptation model that you might see in physical exercise. So if you're trying to improve physical performance, we know that the primary driver of improved cardiovascular fitness or improved muscle size or strength is the stimulus that you apply to it. Right. So the training that you do for your marathon or the lifting you do in the, in the gym, if you're trying to build muscle strength, you can improve how you adapt to those stimuli by attending to your nutrition and attending to your recovery. But the stimulus is the most important thing. Right. I like to lift weights and unfortunately like no matter how many naps and protein shakes I have, I won't get bigger biceps unless I do some bicep curls and the brain, I think, is essentially the same. So the thesis in the book is that how we use our brains is the primary determinant of how they will funct, and that means that we need stimulus. And I know that this is slightly controversial in the current world, where I believe that we're chronically overstimulated while being understimulated at the same time. We're sort of constantly bombarded with multitasking and multimedia and social media and these things that don't truly drive improvements in brain function and feeling overwhelmed because of it, whilst not being able to attend to the real focused deep learning and skill development which is what really drives brain function. And so the stimuli that we can think about that sort of drive this whole system include education and learning, any kind of skill development, be that music, languages, complex motor skills, and then also social interactions, which we know is a primary driver of both human brain evolution and then human brain development and maintenance. So we need to think about, like, how we're using our brains. But then once you've stimulated a region of the brain by engaging it in some task, you need a supply of the things that allow that to happen. So now we're kind of getting into what I call the 3S model. The first S is stimulus, the second S is supply. And so, right, if you activate part of the brain, the local cells, the neurons, the astrocytes, they stimulate the blood vessels to dilate, to widen, to bring in more blood flow. So that's why we need good cardiovascular health. Right? You need that to be able to respond to changes in activity in the brain. And then you also need a supply of energy. So that's where we need good energy regulation, good metabolic health, because glucose, glucose is going to be our primary source of energy. But ketones, lactate, right, those, those, those can play a role too. And then we need a supply of nutrients that kind of run that system. So things that become critical, particularly in terms of dementia risk, are B vitamins associated with methylation, omega 3 fatty acids, vitamin D, iron, and then some others, like magnesium, zinc, antioxidant vitamins like vitamin C, vitamin E, and then the antioxidant polyphenols that you can get from colorful foods. Do a bunch of cool stuff for the brain. There may be some other precursors, like choline or ethanolamine that you can get from eggs or whole grains. Like those kind of provide a structural component and we can get into all of these different sections. But so we've stimulated the brain, we've brought in a supply of things that we need to kind of allow it to do its job. And then just like with our physical performance, you don't get stronger when you're training, you get stronger when you rest and recover afterwards. So this is my third s which is support. So sleep is a critical part of that. That's when all the synapses that you've generated during the day by, through your skill learning are cemented and refined to kind of build part of or like build new aspects of structure and function in the brain. And we can see that with skill learning. We can see the brain change on MRI scans. As these sort of processes are driven even in older adults in their 60s and 70s. Then we can support those processes with what we call trophic factors. So things that like support the growth of synapses and function of neurons in the brain. So one that's produced during exercise is brain derived neurotrophic factor. Hormones play a role here too. I mean, you had an excellent episode with Lisa Moscone, that's really her area of expertise. But hormones sort of support brain function as well. And then we want to avoid things that kind of inhibit the adaptation process. So this is where things like alcohol, smoking, chronic stress, air pollution come into play. And so all of these things interact with. And the reason why I talk about it in this way is because it's not this massive list of 20 things you need to attend to. Because stimulus drives the processes of adaptation and stimulus drives the processes of supply, and supply drives support. They interact. And what you see quite clearly is that when you change one thing, you change lots of things at the same time. So you can. So if you start by stopping smoking, right, you've removed one risk factor. But you will also see improvements in inflammation and improvements in blood pressure. And you're more likely to make other healthy diet, like dietary choices, for example. We know that that happens. Or if you start to sleep better again, blood pressure improves and the next day you feel more social and you're more likely to engage in cognitively stimulating tasks. So I think about it this way, so that there's an in for everybody. And that in could just be one thing. And then the whole sort of network starts to shift in your favor.