All right, Dr. Tommy Wood, there's kind of this old thought that if you resist strain or you have muscle that you're probably not the smartest person in the world. And I know that that's true for me and maybe a couple other people that you guys just published a pretty interesting paper that looked at this basically defined by people that resist strain. Are they actually stupid? And I know that's not literally what the paper was about, but it's basically what it looked at in a weird...
different way. So I'll let you kind of explain what you guys did with this. Cause it's really interesting stuff.
Sure. So I'll, I'll give a little bit of background first. And obviously I study the brain. I'm a neuroscientist.
It's, it's, it's my day job. Um, and I also like to lift weights. So I, um, my, I went to, I went to Vegas with, um, my wife last year and she went to see Thunder from, from down under they were they would try and recruit me which is a very nice compliment on her part i'm not sure that would be true i know exactly i don't have them which actually then is also um it's it's a really big um it's very offensive to brits to be to be confused for australians so that's that's a whole other thing wow we've really started this off badly um Confirming my point.
So I would obviously like it to be the case that if you are more jacked, you are smarter. Right. That would fit. That would fit my personal preferences.
And there is actually some. Data to support some of that. So, or, and a lot of it is epidemiological, but if you look at things like, um, how much brain you have in your skull and that has to be, uh, it has to be. relative to your skull size right because different people are different sizes they have different size skulls they have different size brains that actually isn't related to intelligence or cognitive function at all but how much of your skull is filled with brain is so particularly as you get older you start to lose brain volume and you just have less brain inside that inside the skull um When you look at predicted, like body composition predictors of brain volume, you know, how much brain you have in your skull, um, muscle mass is one of the best predictors that's actually better than, um, uh, fat mass and BMI, uh, in some studies, at least there are also studies that suggest that those who have more muscle mass, uh, have better cognitive function. Uh, that's, they've done that in some.
cohorts like the UK Biobank. And then there are also studies that show that those who have more muscle mass or particularly those who don't have low muscle mass have better maintenance of cognitive function over time. I popped a link down below for Create Creatine Gummies, 50% off of them. So after today's video, check them out. 50% off Allulose Sweetened Gummies.
These have one... 1.5 grams of creatine per gummy. So it makes it so you can low dose your creatine. You're talking about getting in shape for summer Might make some sense helps preserve a little muscle mass by keeping your strength high even if you're in a caloric deficit There's countless bodies of research when it comes down to creatine So I'm not blowing any smoke stuff is legit But the little gummies make it easy to sort of micro dose creatine throughout the day So I find I don't get the water retention that I would get if I were to just drink like a five or ten gram bolus of it at one sitting.
Not to mention 50% off is pretty darn awesome. So that link is in the top line of the description underneath this video. Their new sour apple flavor, holy smokes, especially with no added sugar in it, off the charts.
So there's certainly this idea that those with more muscle mass at the population level have better cognitive function and they're less likely to experience cognitive decline. However, we've actually published similar studies looking at cognitive function and how that relates to body composition. And at least what we found was the most important thing was how functional those muscles are.
So it's not just enough to have big muscles. Those muscles need to be strong as well. They need to be functional because it's probably that function that's driving cognitive function.
So this most recent paper we published, Louisa Nicola was the first author. The idea was to look at whether resistance training, particularly protected regions of the brain that were at risk. in cognitive decline and dementia and to do that using randomized controlled trials of resistance training that then looked at the structure and function of the brain because we know that when we look at epidemiological studies they're observational you don't you can't address causation um you can't really know that it's the bigger muscles that are driving the bigger brains or the or the or the better cognitive function but what we went through first was you know which areas of the brain are particularly at risk in alzheimer's disease which is the commonest cause of dementia and it's the one that i think most people are really concerned about long term in terms of their cognitive function and there are several areas of the brain but um Some of that includes tracts of the white matter, which is the myelinated axon sheaths that are responsible for really fast communication between neurons.
And both the outer layer of the sort of like the wrinkled outer layer of the brain, the gray matter there, the cortex, and then also the deeper parts of the brain and then the rest of the body. So the white matter is really responsible for fast connections. And what the studies show is in individuals, and this is older individuals, either premenopausal and postmenopausal women or both men and women in their sort of 60s and 70s, when they undergo a resistance training program, you start to see improved structure in these white mass tracts in the brain.
And associated with that, you also start to see some significant improvements in cognitive function. So this is like direct interventional evidence that suggests that by lifting weights, and it's very standard weight training programs, you can start to see significant improvements in both brain structure and in brain function. And that's... When you look at that, that's somewhat interlaced also with, I mean, we have some evidence metabolically, not just in structure, that, I mean, resistance training and lactate and whatnot can be supportive of the brain too. So, I mean, there's some other, so this was much more, was this looking at existing bodies of research and kind of just compiling that data?
And then there's some other, I mean, is there other evidence to support resistance training with the brain as far as metabolic function is concerned? I think I've seen some stuff like that. There's. There's probably multiple ways that this could work and could act, and some of it is probably related to myokine release.
We know that as you work the muscles, you're going to release a whole bunch of myokines, including things like brain-derived neurotrophic factor. That seems to be important for maintaining long-term cognitive function and brain structure. We know that as you work the muscles, but also as you...
start to gain muscle tissue you have this bigger buffer for blood sugar regulation and you improve blood sugar regulation and we know that you know because muscle muscle is your most important glucose sink and we know that blood sugar regulation is is critical for long-term cognitive function and the worse your blood sugar regulation the higher hb1c the faster your rate of cognitive decline on average and then another thing could just be the physical and this is probably related to some of the things that you've seen, is that the physical act of lifting weights and particularly learning the new skill of lifting weights, like the motor coordination required to perform the exercises, that you're directly stimulating the brain as you learn those skills and as you work those neuromuscular connections. So I think there's multiple levels at which it seems that resistance training can significantly improve brain health. Is there any benefit to, it's going to sound funny, but sort of the straining that comes and like intracranial pressure, glymphatic clearance, like anything like when you're straining when you're actually like really working hard.
Is there any literature to support that? Because I've kind of thought that before, you know. Because you go in a sauna, our mutual friend, Paula, he's talked about one of the benefits of being in a sauna is you kind of create this intracranial pressure that can help that, which can be good for cerebral spinal fluid and whatnot.
So is there possibly a benefit with sort of the straining and the pressure that's created if you're lifting heavy enough? Or could it be more detrimental? So the straining certainly doesn't seem to be detrimental unless you happen to have an undiscovered aneurysm. And there are certainly people who've had...
uh brain hemorrhages due to straining during weightlifting but it's exceptionally rare so so certainly not something that the people should be worried about but this is an interesting idea and actually we're um In my lab currently, we're using this idea as a potential neuroprotective effect during traumatic brain injury, where you essentially create a simulated Valsalva maneuver. So that's straining. What happens then is you do, you pressurize the vascular system in the brain. And then if the skull is hit, you've essentially created this much stiffer network of blood vessels that stop the brain, the distortion that happens in the brain when your brain gets hit or your head gets hit. So in that set, and there is already some evidence to support this idea, and we're sort of like developing advice and we have a model of TBI or traumatic brain injury or concussion in my lab that we're using for that.
But when you're then thinking about more generally, there's certainly a possibility that this could be beneficial, mainly because. One of the most important things long term for cognitive function is vascular function and the function and health of the blood vessels in the brain. And I mean, also the peripheral body.
And there's kind of this old adage that says that what's good for the heart is good for the brain, generally because you have improved vascular function. And that does seem to be the case. This is important because.
Whenever you do something different with your brain, different regions of the brain become active. And when that happens, you have this thing called neurovascular coupling, which basically means that the neurons that are more active, they then draw in additional blood flow so that you can have more oxygen and nutrients going to that part of the brain. if you don't have a healthy vascular system it can't respond in that way.
So imagine if you had a brain that was just full of atherosclerotic plaques and that's it's an over exaggeration but if you imagine these like really stiff old nasty blood vessels they can't dilate and contract as you as they need to in order to direct blood where it needs to go. So you do need a healthy vascular system. Now one of the main drivers of the function of the vascular system is endothelial function.
So that's the cells that lie in the inside of the blood vessels. And we know that physical activity and the changes in blood flow and blood pressure that come with physical activity, that can help drive endothelial function. And actually having some pressure against the wall of those blood vessels can be important for their function. So hypothetically, when you pressurize the blood vessels in the brain by straining, you could be sort of...
you could almost be training those blood vessels at the same time as you're training the muscle tissue. I don't know if anybody's actually looked at that, but... It's possible that some of the benefit could come from that as well. What about short-term cognitive benefit? So you talked about your paper that's showing sort of a long-term cognitive effect of resistance training.
Any evidence that exercise actually in the short term? You know, there's a lot of anecdotal things out there. A lot of people that talk about how, you know, their brain feels more turned on after they work out.
Personally, you know, after I do like BFR or I do something fairly high intensity. Like I feel like if I don't, as long as I don't gas myself, like that high intensity work, it's like my brain feels turned on. I feel more, but you know, again, I could be placeboing myself into that. It could be purely anecdotal, but is there evidence that even in the short term, like some exercise or resistance training can increase brain function?
Yes. Actually, there's a lot of evidence. What we don't know is the exact dose volume intensity that does it.
But it's certainly, if you look just at aerobic exercise, there are some meta-analyses and systematic reviews. When you look across all the different types of exercise, you can kind of build this picture of what it looks like. So acutely, exercise does seem to improve cognitive function on standardized cognitive function tests. So maybe it's...
the Stroop test, which is a measure of both processing speed and some aspects of executive function, or maybe it's some working memory tests or some other things. You do seem to see Benefit. It's probably, as with most things in exercise, it's probably related to total volume, as in the, you know, intensity times time. So you probably need it to be intense enough for long enough.
So something like going for a jog for like 20 to 30 minutes, that. seems to that's probably been tested most frequently and certainly seems to improve cognitive function um acutely there have also been studies doing say um like high intensity interval training so like 30 seconds max on on a bike with a few minutes rest in between and doing that a few times that's also that there's a study that uses stoop set stoop tests that show that was that was um beneficial the other side of that is It probably needs... It needs to not be fatiguing. Like it shouldn't be max effort. Or if you do do max effort, you shouldn't assess cognitive function immediately afterwards.
So when you and I worked out before a recording, when we sat down for the first few minutes, my brain wasn't working very well because we did a pretty hard workout. From my own anecdotal experience, you can see that, but you can also see that from the literature. So when they've done exhaust, maybe not, fatiguing is maybe not the right word, exhausting exercise. When you really exhaust yourself, that acutely may negatively affect cognitive function.
But in general, doing lower levels of physical activity, lower levels of exercise for, it's probably at least 10 to 15 minutes, again, depending on the intensity. Whereas if it was more intense, you know, maybe just like a few short sprints might. get things get things moving then you do seem to see significant benefits part of it is probably related to so some of it may be related to the things that get released during exercise blood flow all that kind of stuff but part of it might also just generally be related to how arousal affects performance so for any specific function including cognitive functions your level of arousal um So if you imagine a curve and people may have heard of the Yerkes-Dodson arousal curve, it's like really popular in sport in particular because it's an important kind of concept.
But essentially along the bottom you have arousal and on the side on the y-axis you have performance. And for complex skills or complex activities, it's... a bell shape.
So you need some arousal to see optimal performance, but if you're too aroused, it starts to be detrimental. So it's kind of like, if you just kind of wake up and you try and do something cognitively difficult, you're going to be at that bottom end of the bell curve, you're not going to perform as well as you might want to. If you slammed 18 espressos and then tried to do something difficult with your brain, you're going to be hyper aroused and then cognitive function is going to be poor as well.
but there's a sweet spot in the middle. So some of it is probably related to all the other magical things that physical activity does. And then some of it is also going to be related to arousal. And the reason why I say that is then because even though they haven't studied, you know, what's the effect of going, like doing a few quick 10 minute sprints or something on cognitive function, that's something that some of the coaches, so I work in Formula One as primarily in terms of like the athletic world, those kinds of things have been used to kind of you know get people in the zone or get drivers in the zone when they when they have to perform cognitively that's you know driving a formula one car is primarily a cognitive skill although physical physical fitness is important as well but just those short bursts of activity probably going to be probably improve function as well but that may be more related to arousal than related to you know blood flow and some of those other things interesting so when it comes down to Getting the, I mean, you would not want to go more than probably 15, 20 minutes of arousal was sort of your goal in that, right? Yeah.
It just seems like there's, I mean, even as far as performance in the gym is concerned, I noticed that, like, not just cognitively, but arousal is extremely important. Oh, yeah. Like, right? Being able to...
mind muscle connection being able to like if i'm groggy if i'm not aroused then that is a completely i'm having a hard time talking about arousal i've got to be honest so i thought when you're in the gym you want to be aroused all the time all the time and that's why nofap It's absolutely imperative for your gains. But it's very difficult because I have a 12-year-old brain. So, yeah. But it's hard to even like get things moving. So, it's hard to get the weight up.
Oh, wait. There we go again. Anyway, okay.
I'm 12 years old. The point is, it's hard even from a physical standpoint. But if you push it too far, then that arousal kind of goes down.
down. So it's like for me, and that's highly variable. Like if I, I definitely have sort of a, an internal like protocol before I film and things like that.
Part of it is superstition at this point where it's like, I like to do certain things before like a longer filming day that I feel enhance my cognitive function. You know, it's usually. an intense workout, but a short intense workout where I'm not completely fried afterwards. Yeah. And now that you mentioned it, like, I mean, I always chalked it up to like a metabolic thing.
I would do, uh, like BFR for instance, because I thought, okay, maybe, maybe it's the lactate. Maybe there's, and there could be like a metabolic reason behind that. But now that I think about it, there's a level of like the, Like sort of nociception and like the pain that happens with BFR where it's it almost gets you aroused in a weird way because it's a high pain type of movement. Like when you have BFR cuffs on, it's short and it's intense and that pain is just high enough where you kind of feel on. So now I'm almost wondering if it's more that effect.
And doing something short that is relatively painful in terms of exertion is like exactly what I need versus like taxing myself metabolically, which may impede my cognitive performance, you know, four or five, six hours later. Yeah, that's the nice thing about BFR is you get this very significant stimulus without a very large like CNS or like overall body metabolic load. um or demand and that you know so that may be a nice sweet spot um i'd like to you know i'm a big fan of bfr so i'd like to think that um bfr could be the the perfect cognitive enhancer and it certainly makes sense for for why for why that could be the case because you sort of can stimulate some of these pathways without without generating that generating this you know significant um overall fatigue that would last for long periods of time if you know compared to say a very intense sprint session on uh you know the the echo bike or something like that yeah our mutual friend paulie is kind of the one that turned me on to looking at uh differently because i mean as a you know lactate is a signaling device for hypertrophy and all that stuff that's that makes sense and that could be one of the reasons why bfr is good for hypertrophy possibly but i think some of his theories on just like almost getting you to to failure faster and sort of that it almost makes more sense it's like you're able to get to failure and reach in some ways that pain slash kind of even arousal just like it wakes you up in in that sense faster without the metabolic drain yeah right like you've achieved failure significantly faster albeit it comes at a cost of being painful and that's why it's you know not for everybody too because it doesn't exactly feel good um anyhow so i mean that's that's my weird protocol yeah i um i often when When I travel, particularly to give talks and things like that, I'll usually do some BFR before I get on stage. It's mainly to make my guns look better in a T-shirt. That's just it.
But I do notice. that it helps you get switched on without having to be a you know uh more broadly strenuous kind of workout yeah and without being a sweaty mess so it's just interesting because this discussion has given me a different a different spin on it because it wasn't always repeatable if it was something that was just intensity based like yeah uh sometimes it would backfire yeah if i would say okay i'm gonna go run some some intervals or something like that like yeah seven times out of ten i i get lifted up out of it. But those three times it's like, okay, now the whole filming day is ruined because I'm just like, this just pushed me over. Yeah. But now that I think of it, it's like, it's just about getting the right dose to kind of get, get that arousal and kind of wake you up a little bit.
That makes a lot more sense. Yeah. Uh, Dr. Wood, where can everyone find you? Um, best place is probably instagram at dr tommy wood uh posts so papers like this we have we have some more in the pipeline they'll they'll go on there um then i have a podcast about the brain we have a better brain fitness podcast with my friend dr josh turkney who's a neurologist and we also have uh the better brain fitness sub stack which is better brain dot fitness very arousing stuff thank you that's what i always aim for