Chapter 1: What is the main topic discussed in this episode?
Show Me The Science with Professor Luke O'Neill, a Newstalk original podcast. Hello, Luke O'Neill here and welcome to Show Me The Science, my weekly podcast. Well, this week, something very important is happening. The VHI Women's Mini Marathon is happening, 10K. And my wife is also running in this. So hence, it's a big interest in our household.
And my wife is running for Breakthrough Cancer Research. And it's an amazing gathering of people. I've often now watched them running by and all the t-shirts and the causes they're raising money for. Isn't it a wonderful thing? And 10K is no mean feat. I'll tell you that much. And my wife is training every night to do this. That was a great example of people getting out there.
and doing good things for their health. But this week, I'm going to cover the science of exercise and marathon running. Now, I've picked it partly because of the mini marathon that's coming, but also there's a big finding about exercise and why it's good for you. Now, we know exercise is good for us. It's obvious in a way.
But in the last few weeks, a new discovery has been made that it really helps the mind and they're measuring stuff in the brain, basically. and measuring really interesting changes, which I will cover. So exercise is good for your muscles and your health and your heart and all that kind of stuff, but it's also very good for the mind.
And a second big, two big studies actually have come out, very good for depression and anxiety. Now again, anecdotally, we all know taking exercise can help us in going for a run. can lift your mood, but now really good evidence that it's really, really beneficial. And in fact, in that study of the two studies about depression, it was as good as meds and therapy if you take regular exercise.
So really loads of benefits to this across the board. Now, why is it good for us? Well, get your blood pumping, helps your heart. Helps your whole physiology, of course. The current recommendation is 30 minutes of moderate exercise per day. That's the current guidelines. Now, what is moderate exercise? You don't need to go mad. It can be a brisk walk, a swim. Dancing is great.
Even rigorous gardening or, dare I mention, housework. A rigorous go around the house with the Hoover. Get your heart rate up a little bit. is the idea. And if you do it for 30 minutes per day, that is what's recommended and the benefits are manifold.
I mean, as I mentioned, various things like your muscle, obviously, lower risk of heart disease, it'll lower your blood pressure, it'll decrease the risk of type 2 diabetes, which is actually a very common condition, of course. And I guess the reason for this is you're burning glucose. And type 2 diabetes means a bit too much glucose.
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Chapter 2: Why is exercise considered beneficial for our health?
And then the last one is better mental health, which I will come back to. Now, what about this effect in the brain? Well, they looked at this closely inside the skull, as it were, using special imaging technology. Now, it was done in mice. Now, they often look at mice as models of exercise. and they can measure things, and they can measure mice on treadmills. That's where this sort of began.
But they could measure in the brains a real change in the brain happening after exercise. Now, one reason is blood flow flowing around the place, and that seems to affect the brain. But in this study, they measured brain activity using a thing called MRI, which is a fancy machine. They can look inside the brain.
And they saw an increase in activity in a part of the brain called the ventromedial hypothalamus. Now, there's a mouthful for you. VMH for short. It's a specific part of the brain. And this lit up like a Christmas tree during exercise. And secondly, it kept firing at least one hour after the exercise ended.
Now, that got them because, you know, that part of the brain in particular seemed to be going on fire as well in a very beneficial way. And not only that, but kept firing, you know, an hour after you stopped exercise.
And after two weeks of this and measuring it and looking at the program in the brain, the mice in particular were much more able to run faster, could run for longer on the treadmill. Now, of course, that's partly training and anybody training for the marathon or the mini marathon will notice them getting better. But it turns out that that increased endurance was because of the VMH.
Isn't that incredible? Because the scientists could do something very clever. They could interfere with the VMH using a special approach, which I can't come into, it's a bit complicated. But if you stop the VMH firing, right, the mice could not develop this endurance. Now, doesn't that tell you something interesting? It's not just about their muscles then getting stronger.
There's something happening in the brain. that allows them to be better able to exercise next time. And when they interfered with this VMH region, first of all, the mice didn't improve over time in terms of their capacity for endurance, but they got much more fatigued as well after exercise. There's something going on in this part of the brain as to how the body adapts during exercise.
Now, what I like about this is the lead scientist, his name is Nicholas Petley, he said, when we lift weights, we think we're just building muscle. It turns out we might be building up our brain as well. And he was referring to this VMH region of the brain. And again, even better, and as anybody who listens to the podcast will know, I like mechanism, like what's really going on here.
It turns out that that part of the brain, the VMH, was tied into glucose storage. So when you trigger that part of the brain through exercise, your body's able to store more glucose in the form of glycogen, which I will come back to when I come to the marathon part. And that meant you'd better sort of stores in reserve. And that meant you were more able to run longer the next time.
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Chapter 3: What are the current exercise guidelines recommended?
Maybe it's because the VMH is a bit less active as we age. Now, they haven't shown that, but you can speculate on that a bit. So therefore, you can imagine when you're in your 60s or 70s or whatever it is, get the VMH going with some electrode, and now you'd be able to walk further. Wouldn't that be amazing?
That's still a bit speculative, but certainly that might be one consequence of this discovery. It'll help older people take more exercise is the overall idea, is what we're saying. And what's important here, as I say, it is about the brain. The second bit then is this business of depression and anxiety. Now, it's obvious, as I say, we've known exercise helps our mood.
But now two major studies just published earlier this year have found that regular exercise is as good as antidepressants or therapy for those struggling with their mental health. Isn't that a great thing to read? And the first study was remarkable. They looked at 69 trials of this.
Chapter 4: Is housework comparable to running for heart health?
Now, people have done like almost like a clinical trial. If someone's got anxiety, depression, take exercise, they feel a bit better. 69 trials showed definite benefit. Another trial involving 80,000 people. Now, whenever I see those kinds of numbers, I go, oh, there's something going on here. That second study was 1,000 separate trials.
And both trials combined, exercise decreases symptoms of depression and anxiety as much as regular treatments. Isn't that incredible? And exercising in groups, it turns out, was especially good for those who suffered from depression. And there's a social aspect there that lifts them, I guess.
Anxiety was low intensity exercises seem to benefit people with anxiety, like going for a good walk, for instance. So, again, really strong scientific evidence that exercise can benefit people who are suffering certain mental health issues, especially depression and also anxiety. Now, the mechanism isn't getting back to the mechanism again.
The first idea here that we're kicking around for a good 20, 30 years now is after you exercise, you make endorphins. You may have heard of them. They are the so-called happy hormones, right? And we've all heard of endorphins, haven't we? And they go up when you exercise was the claim. And they make you feel better. They couldn't find evidence for that, right?
They looked closely at this, measuring them in saliva and various things. And there was no real evidence that endorphins were working in this way. And in fact, they could block endorphins as a way to block the receptors for endorphins. And they tried those in people who were runners, and it didn't affect the mood lift. That is good evidence, isn't it?
So in other words, you go for a run, you feel a bit better. Is it endorphins? If you block them, you still feel better. So it wasn't endorphins. And then the question is, well, what is it? Well, a second family of happy hormones, as it were, are called endocannabinoids. Now, there's a mouthful for you. They've been studied a lot. They do improve mood, make you feel a bit happier.
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Chapter 5: What changes occur in the brain after exercising?
And guess what? They were the ones they think that might be involved. And the endocannabinoids are creating that well-being after exercise. So at the moment, we're leaning towards endocannabinoids. Now, guess what? Endocannabinoids are very similar to
to the drugs that we found in cannabis and marijuana cannabis cannabinoid so in other words if you take exercise you're getting a natural high just as if you might have taken a bit of cannabis is the idea i suppose because what's in cannabis then is mimicking the natural happy hormone in your body the endocannabinoid so again that's quite an interesting connection there so a really healthy way to boost your own endocannabinoids is through exercise so isn't that great to uh
to read as well. But as I say, the evidence now is so compelling that this is beneficial to mood, right? And again, 30 minutes per day is all you need. Another study while I'm at it, because it is the weekend of the mini marathon, another study of 17,000 adults, right, showed this 30 minutes per day. was good, right? And the average age of the people in that was 57.
So it was never too late to take this up, I guess. Now, let's now have a look at the marathon, right? What does it do to your body and the science behind this? There's been loads of studies on how marathon running and all this sort of stuff does to your body because it's quite a stressful thing, isn't it? There is a science behind marathons. Now, 10K is a fair old effort, remember.
Not a full marathon, but still a huge amount of effort. And very interesting things happen in your body. It's called aerobic endurance because you're breathing in and you're exercising in an aerobic way. If you do weights, that's called anaerobic because you don't need as much oxygen for your muscles when you do weightlifting. But in this case, you're breathing very fast.
and all the oxygen is going in and then your muscles are making ATP. ATP is the battery of life, remember, the key biochemical from which we get energy, very importantly. So you make loads of ATP and that gets the muscles going, the energy is coming from the ATP. And you burn, glucose obviously is the source of energy, fats as well, fatty acids, and the very important thing called glycogen.
And this gets back to the VMH in a way, because you have your own storage of glucose, mainly in your liver, in the form of this thing called glycogen. So in other words, we always have a reserve of glucose in our bodies in the form of glycogen. And glycogen is a polymer of glucose. It's those glucose molecules all attached together. Now when you run, especially in these endurance races,
running events like the 10K, you burn the glycogen and that releases glucose into your bloodstream. And it's obvious in a way because you need energy, don't you, when you're running for 10K. And so you will begin to take the glucose from the glycogen and your body burns the glucose to make the ATP that keeps the muscles going. So that's where the energetics of marathons come from.
And then very interestingly, and again, biochemists work this out, if you run a marathon, people hit what's called the wall. And it's a sudden onset of fatigue, and they've got to push on through the wall. It's usually after 30 kilometers. which is maybe, what, two-thirds of the way through a marathon. It won't happen on the 10K, probably, because it's not long enough for this.
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Chapter 6: What role does the VMH play in exercise endurance?
One of the big effects is you get better able to handle lactate. lactate coming off the glucose, as I say, as a kind of a byproduct from the engine burning, as it were. You can keep lactate levels low if you train, and then you're probably going to be okay. And then lastly, and not least, and I've mentioned it a few times, it's all about the brain as well.
And exercise and training means you'll feel less fatigued because the brain adapts. The VMH, as I mentioned, isn't it great? And the psychology of this is important as well. You're in the zone, you know, you get running and then you're prepared for this, I suppose, psychologically as well. So there's a psychological aspect to this. I bet you never knew there was so much going on.
when it comes to exercise and in particular running the 10K. And good luck to everybody running in the 10K. Great, you're raising money for all those great causes. Your VMH will thank you and your whole body will be wonderful two or three days later. It's a wonderful thing to do. So there you have it. That's the science of exercise and the marathon. And thanks for listening as ever.
And my podcast is a new stock production available every Thursday, wherever you get your podcasts.