Latest / Hardiness with Dr Paul Taylor / Want to protect and improve your brain? Make this a habit. Wisdom Wednesdays

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Want to protect and improve your brain? Make this a habit. Wisdom Wednesdays · Hardiness with Dr Paul Taylor

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  Speaker 1: Hey, everyone, welcome to another edition of Wisdom Wednesdays. Now,
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  Speaker 1: today I want to talk about a topic that is
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  Speaker 1: really underappreciated in the exercise in brain health space, and
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  Speaker 1: that is resistance training and its potential neuroprotective effects. Now,
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  Speaker 1: most of you will be familiar with the idea that
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  Speaker 1: aerobic or cardiovascar exercise is good for the brain, and
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  Speaker 1: that has been very, very well established for quite a
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  Speaker 1: few decades. But what's emerging lately is that resistance training,
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  Speaker 1: lifting heavy shit as I like to call it, may
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  Speaker 1: have distinct and complementary effects, particularly when it comes to
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  Speaker 1: cerebralovascular health, brain structure, and cognitive function. And the paper
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  Speaker 1: that we're going to discuss today is a really comprehensive
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  Speaker 1: review that tries to peace the together exactly how resistance
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  Speaker 1: training might influence the brain, particularly in the context of
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  Speaker 1: the aging brain and neurodegenerative diseases like Alzheimer's disease, and
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  Speaker 1: also mild cognitive decline and other forms of dementia.
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  Speaker 2: So why does this matter. Let's get a bit of
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  Speaker 2: context first.
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  Speaker 1: One of the early features of cognitive decline and diseases
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  Speaker 1: like Alzheimer's is reduced cerebral blood flow. And I talked
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  Speaker 1: about this last week when I was talking about peanuts
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  Speaker 1: and rebel blood flow. But essentially it means that brain
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  Speaker 1: isn't being perfused as effectively. Blood isn't getting there as
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  Speaker 1: effectively as it should do. And importantly, this happens before
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  Speaker 1: you see obvious symptoms like memory loss or general loss
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  Speaker 1: of cognitive decline or so our general cognitive decline. Now
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  Speaker 1: alongside that, and there's also mechanisms such as increased inflammation
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  Speaker 1: in the brain, increased oxidatives, dress im per glucose metabolism
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  Speaker 1: in the brain. You may have heard me talk about
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  Speaker 1: Alzheimer's disease being called type three diabetes. And the other
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  Speaker 1: thing is dysfunction of the blood brain barrier, right, that
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  Speaker 1: critical barrier between your brain and the rest of the
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  Speaker 1: body that stops certain.
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  Speaker 2: Things getting into the brain.
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  Speaker 1: And all of these things contribute to a perfect storm
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  Speaker 1: for neurodegeneration. Now, traditionally, aerobic or cardiovascar exercise is been
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  Speaker 1: the go to intervention, but this paper makes the point
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  Speaker 1: that muscle strength itself is strongly associated with better cognitive
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  Speaker 1: outcomes and reduced dementia risk. And I've talked about this before,
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  Speaker 1: and that's clearly where resistance training comes in. So what
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  Speaker 1: did the paper actually do? So it wasn't a single experiment,
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  Speaker 1: It was a narrative review. So what the authors did
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  Speaker 1: is they pulled data from human trials, from animal studies,
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  Speaker 1: and from mechanistic research, and they screened over seven thousand
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  Speaker 1: papers and they narrowed that down to around one hundred
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  Speaker 1: and seventy high quality relevant studies looking at resistance training
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  Speaker 1: and outcomes such as cerebral blood flow, vascular function, brain structure,
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  Speaker 1: neurotropic or nerve growth factors like BDNF and IGF one,
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  Speaker 1: and also cognitive performance studies.
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  Speaker 2: So what we're.
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  Speaker 1: Getting here is a real big picture synthesis rather than
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  Speaker 1: one isolated finding. And in the big tip takeaway, if
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  Speaker 1: you had to summarize the paper in oneline, it would
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  Speaker 1: be this.
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  Speaker 2: Resistance training likely supports brain.
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  Speaker 1: Health through vascular, metabolic, and neurochemical pathways and may help
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  Speaker 1: slow age related cognitive decline. Now let's break that down
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  Speaker 1: because the mechanisms is what I find particularly interesting. So
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  Speaker 1: the first mechanism vascular and blood flow adaptation. So that's
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  Speaker 1: one of the set themes in the paper. It's about
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  Speaker 1: cerebrovascular function. Now, resistance training creates a very unique stimulus
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  Speaker 1: unlike steady state cardio. You know, there's a lot of
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  Speaker 1: talk about zone two out there, but unlike that, it
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  Speaker 1: produces rapid spikes and drops in blood pressure with each repetition,
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  Speaker 1: and you see huge changes, particularly if you're lifting really
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  Speaker 1: heavy stuff, if you're doing heavy deadlifts or squats, like
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  Speaker 1: the changes in blood pressure are ridiculous. Now, that might
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  Speaker 1: sound like a negative thing, but the authors and many
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  Speaker 1: other people argue that it's actually beneficial. Why because over time,
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  Speaker 1: this repeated pressure challenge may improve the brain's ability to
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  Speaker 1: regulate blood flow. It enhances cerebral autoregulation and improves the
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  Speaker 1: ability to buffer pressure changes. So it's basically stress inoculation training. Now,
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  Speaker 1: there's also evidence that resistance training improves endotherial function, so
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  Speaker 1: endothereal sales that they're the things that make up your
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  Speaker 1: cardiovascular system. It increases nitric oxide availability, and nitric oxide
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  Speaker 1: really relaxes all of your veins and arteries, and it
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  Speaker 1: also can increase regional cerebral blood flow, including areas like
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  Speaker 1: the hippocampus and the temporal lobe, which tend to be
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  Speaker 1: really effective in cognitive de client and they're heavily involved
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  Speaker 1: in memory, and they're actually some of the first that
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  Speaker 1: are affected in Alzheimer's disease. So similar to the peanut
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  Speaker 1: study that I discussed last week, again we see this thing.
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  Speaker 1: Better vascular function is better brain function. Now, the second
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  Speaker 1: mechanism is a reduction in inflammation and oxidative stress. So
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  Speaker 1: a major mechanism pretty much every chronic disease is inflammation,
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  Speaker 1: that cellular inflammation in that chronic low grade inflammation, especially
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  Speaker 1: when combined with oxidative stress. They are now recognized as
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  Speaker 1: key drivers of neurodegeneration. Now, interestingly, acute resistance exercise increases
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  Speaker 1: oxidative stress and inflammation temporarily, but chronic resistance training appears
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  Speaker 1: to reduce baseline levels. So again this is like many
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  Speaker 1: different things, it's a harmetic response. You get a negative
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  Speaker 1: effect very transiently, but then the body rebounds and there's
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  Speaker 1: a positive effect. Now in both animal and human studies,
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  Speaker 1: resistance training has been shown to reduce inflammation markers like
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  Speaker 1: into looking six and TNF alpha tumor and ne croxius
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  Speaker 1: factor alpha. It also improves antioxidant defenses, and it reduces
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  Speaker 1: what's called lipid perryoxidation. That's a marker of oxidative damage.
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  Speaker 1: So over time you're essentially shifting the body towards a
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  Speaker 1: less inflammatory, more resilient state, which is protective for the brain. Now,
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  Speaker 1: the third mechanism that they explored was the effects on
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  Speaker 1: Alzheimer's pathology directly, and this is where it gets really interesting.
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  Speaker 1: So on animal models of Alzheimer's disease, resistance training has
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  Speaker 1: been shown to reduce amyloid beta accumulation. You probably have
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  Speaker 1: heard of amyloid beta. It also improves TAW pathology, so
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  Speaker 1: and enhances clearance mechanisms in the brain.
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  Speaker 2: This is really really important.
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  Speaker 1: So one proposed mechanism here is improved blood brain barrier
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  Speaker 1: integrity that helps to remove the toxic proteins from the brain.
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  Speaker 2: Now, this is mostly animal.
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  Speaker 1: Data because it's real you can't do those sorts of
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  Speaker 1: studies on humans. So we don't have strong human trials
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  Speaker 1: showing that lifting me it reduces amyloid plaques, but we
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  Speaker 1: can actually now measure that amyloid and blood flow. So
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  Speaker 1: just sort of standby for more research in this area.
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  Speaker 1: But mechanistically it's a very very plausible pathway and that
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  Speaker 1: helps to build the evidence. Now the fourth one, this
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  Speaker 1: is pretty kneeled on for me. I really explored this
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  Speaker 1: in my PhD, and this is neurotropic factors, nerve growth factors,
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  Speaker 1: particularly BDNF, which I'm a big fan of, and IGF one.
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  Speaker 1: So BDNF, if you haven't heard me talk about it,
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  Speaker 1: brain derived neurotropic factor. Neurotropic means nerve growth. It is
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  Speaker 1: being described as fertilizer for the brain because it supports
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  Speaker 1: learning and memory, synaptic plasticity, and also neurogenesis the creation
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  Speaker 1: of new brain sales. So in studies, resistance training increases
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  Speaker 1: BDNF acutely after each session, and there's potentially it provides
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  Speaker 1: repeated doses of BDNF over time. This is very similar
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  Speaker 1: to a cardiovascar exercise, particularly high intensity interval training, because
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  Speaker 1: we see the BDNAF spikes when you're producing lactiate or
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  Speaker 1: lactic acid, and actually lactia crosses the bloodbeam barrier triggers
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  Speaker 1: the release of BDNF. And this is important because the
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  Speaker 1: evidence for long term increases in basline BDNF is pretty mixed,
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  Speaker 1: so it seems to be that the benefit may come
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  Speaker 1: from more frequent transient spikes, just giving a little spike
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  Speaker 1: here and a little spike there rather than increasing the
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  Speaker 1: level at rest. Then there's IGF one, So that's another
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  Speaker 1: growth factor, and it's also contributes to neurogenesis, synaptic function,
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  Speaker 1: and possibly reduced amyloid accumulation. And again resistance training is
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  Speaker 1: known to really increase IGF one acutely, but again long
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  Speaker 1: term changes are pretty inconsistent. It seems to be that
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  Speaker 1: these growth factors, they certainly contribute, and it's the intermittent
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  Speaker 1: spikes that you're getting from regular training that seems to
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  Speaker 1: be beneficial, but it's just one piece of a much
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  Speaker 1: bigger puzzle.
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  Speaker 2: So the fifth.
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  Speaker 1: Mechanism that they explored were cognitive and neurological effects.
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  Speaker 2: So what about actual brain outcomes?
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  Speaker 1: Now, there is accumulating evidence that resistance training can improve
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  Speaker 1: executive function, it can improve memory, and it can enhance
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  Speaker 1: functional connectivity in the brain. And some imagen studies that
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  Speaker 1: the author's reference show increased activities in regions like the
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  Speaker 1: temporal and parietal loops, and these are the loobes that
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  Speaker 1: tend to be affected in some types of dementia, and
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  Speaker 1: also improvements in markers of neuronal integrity, So the sort
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  Speaker 1: of structure or integrity of your neurons. Now, this is
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  Speaker 1: an interesting angle and it shows but because if you
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  Speaker 1: think about it, resistance training, it's not just physical, it's
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  Speaker 1: also cognitively demanding.
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  Speaker 2: You know, you're learning new movement.
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  Speaker 1: Patterns, you're coordinate the adding multiple muscle groups. Particularly, This
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  Speaker 1: is why I'm a big fan. You know, you can
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  Speaker 1: start off on machines, but you've got to go to
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  Speaker 1: freeways because that coordination through your nervous system is hugely,
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  Speaker 1: hugely important. You've also got to track your reps and sets,
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  Speaker 1: you've got to control your breeding.
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  Speaker 2: So it may actually.
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  Speaker 1: Be a kind of form of cognitive training in and
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  Speaker 1: of itself. And then you get all the other growth
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  Speaker 1: factors and things that we talked about, and the mechanisms
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  Speaker 1: add to each other, so then there's there's other indirect mechanism.
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  Speaker 1: I really like the way they explored this. So sleep
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  Speaker 1: and metabolism so so too. These are two that they
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  Speaker 1: are really worth mentioning. So resistance training has consistently been
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  Speaker 1: shown to improve sleep quality and increase the time spent
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  Speaker 1: in deeper sleep because your body needs to repair itself and.
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  Speaker 3: That's crucial because deep sleep is when your glymphatic system,
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  Speaker 3: the kind of lymphatic system of the BRI and the
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  Speaker 3: glymphatic system switches on massively and deep sleep and it
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  Speaker 3: clears amyloid beta and the tauel proteins and other metabolic
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  Speaker 3: waste products that you're producing each dage you ask from
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  Speaker 3: your neurons using oxygen to create energy.
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  Speaker 1: They also talked about metabolic health and resistance training has
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  Speaker 1: been shown to massively improve incial insensitivity and glucose metabolism.
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  Speaker 1: And we know that impert glucose metabolism is an early
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  Speaker 1: feature of cognitive line and Alzheimer's disease, and this is
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  Speaker 1: definitely another key pathway. I mean, I've talked about it
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  Speaker 1: several times about Alzheimer's being called.
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  Speaker 2: Type three diabetes.
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  Speaker 1: So resistance training is very very good and improved being
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  Speaker 1: glucose metabolism and insolent sensitivity. So when you put all
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  Speaker 1: of this together, resistance training appears to influence brain health
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  Speaker 1: through multiple overlapping mechanisms. The first is vascular, so improved
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  Speaker 1: blood flow and pressure regulation. The second is anti inflammatory,
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  Speaker 1: which ends up in reduced chronic inflammation. The third is neurochemical.
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  Speaker 1: More BDNF more IGF one better neuroplasticity. The fourth is
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  Speaker 1: metabolic improved glucose handling and disposal, and the f it
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  Speaker 1: is behavior of better sleep and cognitive engagement. And importantly,
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  Speaker 1: these effects are complementary to cardiovascular exercise, not a replacement.
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  Speaker 1: So let's talk about it a few caveats. A lot
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  Speaker 1: of the mechanistic work comes from animal studies, but these
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  Speaker 1: are plausible mechanisms in humans as well. Right now, human
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  Speaker 1: trials that they're still relatively limited, and we don't yet
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  Speaker 1: have definitive evidence that resistance training alone prevents dementia.
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  Speaker 2: But I would say watch this space because there's.
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  Speaker 1: More and more research thanw I being done in resistance training.
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  Speaker 1: For thirty years, it was all about cardiovascular training. But
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  Speaker 1: now there's heaps of researchers and more research coming out
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  Speaker 1: every month on the benefits of resistance training, and I
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  Speaker 1: think it's a very important and currently underutilized tool for
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  Speaker 1: supporting brain health. As we yeus because we know that
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  Speaker 1: many many adults. You know, when you look at the
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  Speaker 1: recommendations for physical activity, if you pick Australia, about sixty
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  Speaker 1: percent of adults hit the biggest line, the bottom recommendation
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  Speaker 1: of one hundred and fifty to three hundred minutes. But
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  Speaker 1: when it comes to also incorporating strength training twice a week,
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  Speaker 1: only twenty percent of older adults actually do that, and
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  Speaker 1: it's hugely.
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  Speaker 2: Important that we do it. This is about you.
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  Speaker 1: You just can't just do cardio. You've also got to
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  Speaker 1: lift heavy shit like. Cardio is great for your cardiovascular fitness,
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  Speaker 1: but resistance training is important for strength, metabolism and vascular resilience,
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  Speaker 1: so ideally you need a combination of both. That's it
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  Speaker 1: for this week, folks, catch you next time.