Speaker 1: Hey, everybody, welcome to another edition of Wisdom Wednesdays. Today
Speaker 1: we are going to dive into something that is not
Speaker 1: just fascinating, but it's also pretty personal for me because
Speaker 1: we're going to talk about the heart, Your heart, my heart,
Speaker 1: and how incredibly malleable are plastic it really is. And
Speaker 1: if you're not a regular listener, and this is personal
Speaker 1: for me because in January this year, I went through
Speaker 1: open heart surgery to correct a dodgy aortic valve that
Speaker 1: I was actually born with. So we're going to talk
Speaker 1: about today through the lens of one of the most
Speaker 1: groundbreaking studies ever in exercise science, and it's called the
Speaker 1: Dallas bed Rest Study. And then there's been a series
Speaker 1: of studies after that about the Dallas bed Rest and
Speaker 1: Retraining Study and it's kind of got a fifty year
Speaker 1: legacy and this researchs really changed medicine. And after my
Speaker 1: own experience with heart surgery, I can tell you that
Speaker 1: this isn't just theory, it's actually life saving knowledge. And
Speaker 1: it starts. The story starts in nineteen sixty six, five
Speaker 1: healthy young men in their early twenties, fit and no
Speaker 1: health issues, volunteered for a radical experiment what they had
Speaker 1: to do was lie flat on their backs for three weeks.
Speaker 1: No walking, no standing, no sleeky lapse to the fridge,
Speaker 1: just bed rest and probably a student's dream get paid
Speaker 1: to lie in bed for three weeks, But what happened
Speaker 1: was a bit of a wake up call. In just
Speaker 1: twenty one days of complete inactivity, there are cardiovascular systems
Speaker 1: aged by what would normally take thirty years of living.
Speaker 1: Their VO two max, which is they measure the gold
Speaker 1: standard measure of your cardio respiratory fitness or horsepower if
Speaker 1: you like it, actually dropped by twenty seven percent in
Speaker 1: three weeks, and their cardiac output, which is how much
Speaker 1: your blood how much blood sorry, your heart pumps per
Speaker 1: minute plummeted by twenty six percent, and the stroke volume,
Speaker 1: the amount of blood that's pushed out per heartbeat, dropped
Speaker 1: a whopping thirty one percent, and its submaxim sub maximal effort.
Speaker 1: Just like light cycling or light jogging, Their heart rate
Speaker 1: and blood pressure skyrocketed. Their hearts were working harder, just
Speaker 1: doing less, And this was the original use it or
Speaker 1: Lose it research study, But then came a bit of
Speaker 1: a twist. These men spent the next eight weeks in
Speaker 1: a structured endurance training program. And this wasn't a walk
Speaker 1: through the park. It was rigorous aerobic and anaerobic training
Speaker 1: and it was five to six hours per week and
Speaker 1: the results were pretty bloody stunning. Their VO two macs
Speaker 1: increased by forty five percent, so went way above what
Speaker 1: they were before they came in. Their stroke volume jumped
Speaker 1: forty eight percent, and their cardiac output and returned to
Speaker 1: it and actually even surpassed their baseline levels. And the
Speaker 1: cardiovascular damage from complete rest was not just reversible, it
Speaker 1: was reversible and actually went higher through targeted, consistent effort.
Speaker 1: And remember this wasn't just a theoretical benefit. This is
Speaker 1: actually a seismic shift in how heart attacks were treated
Speaker 1: from their on no more prolonged bed rest after heart attacks.
Speaker 1: This was the genesis of cardiac rehabilitation. And if we
Speaker 1: fast forward thirty years, the researchers tracked down the same
Speaker 1: thive men, now all still in their fifties, and they
Speaker 1: tested them again. This time there was no bad rest.
Speaker 1: They just wanted to examine how three decades of normal
Speaker 1: aging had impacted their hearts, and to the researcher surprise,
Speaker 1: their VO two max had only declined by twelve percent
Speaker 1: in thirty years, and compare that to the twenty seven
Speaker 1: percent crash after three weeks of bad rest. Now, what
Speaker 1: probably happened was that training study that they did. That
Speaker 1: they went through. The bed rest and training study probably
Speaker 1: locked in for these guys the importance of fitness, and
Speaker 1: so they probably had lifelong exercise and that's why their
Speaker 1: hearts when they were in their fifties actually seemed a
Speaker 1: lot better than what was the original thirty years of aging. Right,
Speaker 1: But this time they actually trained these guys again, but
Speaker 1: this was a bit of a gentler program, and it
Speaker 1: was long. It was two hundred and fifty minutes a week,
Speaker 1: and it was progressive overload. Right. They didn't start them
Speaker 1: as hard as they did when they were younger. They
Speaker 1: built it up over time. But again they got significant
Speaker 1: gains their VEO two max roles fourteen percent, right, not
Speaker 1: quite as much as in their youth, but that's that's massive. Like,
Speaker 1: if you're in your fifties and you can increase your
Speaker 1: VO two max by fourteen percent, that has a really
Speaker 1: profound effect on your risk of all cause mortality. Now,
Speaker 1: let's bring this study forward now into the future. Twenty eighteen,
Speaker 1: the same research team and this was at Dallas. They
Speaker 1: asked a big question, can you reverse cardiac aging in
Speaker 1: the middle age, not with a late level training, but
Speaker 1: with a doable, realistic, although reasonably vigorous exercise plan. So
Speaker 1: what they did is they recruited sixty one healthy but
Speaker 1: sedentary middle aged adult typical population and their average age
Speaker 1: was fifty three. Half of them and were assigned a
Speaker 1: low intensity stretching and yoga control right, So these were
Speaker 1: the control group. They didn't do nothing, they were doing
Speaker 1: low intensity exercise and the other half got a smart
Speaker 1: structured training program. And this was two years and the
Speaker 1: key ingredients of this program and I will send a
Speaker 1: link to this if you want to really get in
Speaker 1: and geek out, but essentially it was four to five
Speaker 1: days of training per week and it started off with
Speaker 1: moderate intensity aerobic work what we call zone two. Now
Speaker 1: you may have heard of zone two. That's in terms
Speaker 1: of heart rate training zones, and it's sixty to seventy
Speaker 1: percent of your maximum heart rate. This is the bread
Speaker 1: and butter of endurance training. And if you don't have
Speaker 1: a heart rate monitor, you don't know your maximum heartbrate.
Speaker 1: The easiest explanation of zone too is you can talk,
Speaker 1: but you can't sing, right, So you should be able
Speaker 1: to hold a conversation, but somebody should know if they're
Speaker 1: talking to you on the phone that you're actually exercising.
Speaker 1: If you can sing, you're in zone one. If you
Speaker 1: can't talk in full sentences, you're in zone three or higher. Now,
Speaker 1: this modern intensity aerobic work is really important because it
Speaker 1: is very very beneficial for our mitochondria and gives us
Speaker 1: what we call an aerobic base. And then they added
Speaker 1: in high intensity intervals and specifically they used my favorite
Speaker 1: protocol and the one that I'm actually using for my
Speaker 1: cardiac rehab, and it's their Norwegian style four x four protocol.
Speaker 1: So what you do is you go four minutes hard
Speaker 1: and at the end of those four minutes you should
Speaker 1: be at ninety to ninety five percent of your max
Speaker 1: heart rate or a perceived exertion of nine out of ten. Right,
Speaker 1: So you do that for four minutes. Then you have
Speaker 1: three minutes of active recovery down to about zone two
Speaker 1: just to count, so you're keeping moving but at low
Speaker 1: intensity that three minute recovery, and you do four intervals, right,
Speaker 1: So it's four intervals with three recovery it's twenty five
Speaker 1: minutes in total. And then they added into this one
Speaker 1: long weekly session of endurance training and importantly as well,
Speaker 1: they did twice weekly all body strength training. Right, so
Speaker 1: this wasn't brutal, but it was a pretty reasonable, vigorous
Speaker 1: exercise program, and it was calculated and it paid off.
Speaker 1: After two years of this training, their VO two max
Speaker 1: increased by eighteen percent. Now, this is a massive improvement
Speaker 1: in middle age. And like I said earlier on this,
Speaker 1: if you're in your fifties and you can increase your
Speaker 1: VO two max by eighteen percent, there's not much else
Speaker 1: out there that you could do that would juice your
Speaker 1: risk of all cause mortality as much as increasing your
Speaker 1: view two march by eighteen percent. But there was a
Speaker 1: deeper win here. Their hearts actually got younger. So when
Speaker 1: they really dug into looking at how their heart was performing,
Speaker 1: their left ventricular stiffness. So you're left ventrical, that's that
Speaker 1: you think about that the rooms of your heart, if
Speaker 1: you like you're left ventricle, is this important room? This
Speaker 1: is this is where the heart, the heart or the
Speaker 1: chamber that fills up with blood and then it squeezes
Speaker 1: and that's when your heart beats and actually pumps the
Speaker 1: blood throughout your body. So your left fend. The stiffness
Speaker 1: of your left ventricle, essentially how rigid or elastic it is,
Speaker 1: is really important. And in these guys, their left ventricular
Speaker 1: stiffness drops significantly. That meant that the heart could relax better,
Speaker 1: it could fill more efficiently, and it could pump more
Speaker 1: blood per beat. Now this is really important. So with me,
Speaker 1: when I had that dodgy aortic valve, a bicuspit valve,
Speaker 1: what that meant was every time that blood pumped out
Speaker 1: of the left ventricle, and because my valve didn't shut correctly,
Speaker 1: over time, some of the blood came back in and
Speaker 1: that stretched the left ventricle. Now I was lucky that
Speaker 1: I caught it relatively early. If I'd have waited another
Speaker 1: year eighteen months, my left ventricle would have got much
Speaker 1: stiffer and also would have stretched to the point of
Speaker 1: no return. And that's what we call heart failure. When
Speaker 1: you hear of heart failure, that's what it is. You're
Speaker 1: left ventricle is actually stretching to the part of no return,
Speaker 1: and it gets really stiff and it just does not
Speaker 1: work well. Now, what also happened in these people is
Speaker 1: their stroke volume also went up. The amount of blood
Speaker 1: that they could pump out with every heartbeat, right, which
Speaker 1: is really important. The heart size actually increase, So this
Speaker 1: is a physiological adaptation. And a result of all of
Speaker 1: that is that the resting heart rate went down because
Speaker 1: the heart, because it was more efficient, didn't have to
Speaker 1: beat as often. In real terms, this meant that they
Speaker 1: were fitter, they have more efficient and more youthful hearts.
Speaker 1: And in the control group, they didn't have any change,
Speaker 1: any positive change. In fact, their heart function decline because
Speaker 1: remember this is a two year study and they were
Speaker 1: two years older and they had that two years of decline.
Speaker 1: So let's break this down really simply in Layman's terms. So,
Speaker 1: when your heart becomes stiff, that left ventricular stiffness, it
Speaker 1: loses its ability to relax and fill with blood efficiently.
Speaker 1: That is a direct pathway to heart failure with preserved
Speaker 1: dejection fraction. That's what we talk about, and that's an
Speaker 1: increasingly common and stubborn form of heart failure, especially and
Speaker 1: older adults. And here's the kicker that twenty eighteen studies
Speaker 1: showed that this trajectory is not inevitable. If you intervene
Speaker 1: in middle age, you can stop this stiffness from setting
Speaker 1: in the heart remains plastic or changeable into your fifties
Speaker 1: and beyond. Now, the same research group did another study
Speaker 1: where they took people in their sixties and they trained them,
Speaker 1: and they didn't see the same results, right, So part
Speaker 1: of that conclusion was you got to get on this
Speaker 1: when you're in their fifties. But actually, when you look
Speaker 1: into the detail, they did admit that the training intervention
Speaker 1: that they did in the sixties wasn't as comprehensive as
Speaker 1: the training intervention in the fifties. So there's still a
Speaker 1: little bit of a question. But what we do though
Speaker 1: is as your heart ages, it like all tissues in
Speaker 1: the body, they lose their elasticity, right, So what does
Speaker 1: this mean. It means that a couple of things. Number One,
Speaker 1: your heart remembers. It remembers that three weeks of doing
Speaker 1: nothing can wreck you more than three decades of aging.
Speaker 1: So we have to be moving if we want to
Speaker 1: have a healthy heart. But it also means that consistent
Speaker 1: smart exercise, especially when it includes a mix of baseline
Speaker 1: aerobic zone two and high intensity interval training that doesn't
Speaker 1: just increase your fitness. This is about cardiac uth. It's
Speaker 1: about making your heart younger, and if your heart gives up,
Speaker 1: it's all over, right, And we're not talking about marathons here, right.
Speaker 1: That twenty eighteen study met the public health guidelines right,
Speaker 1: one hundred and fifty to three hundred minutes a week,
Speaker 1: with some of it high intensity interval trainings and strength training.
Speaker 1: I think that's also important in this study. It is achievable,
Speaker 1: it is sustainable, but you've got to do the work.
Speaker 1: That's the key thing. So the big take home here
Speaker 1: is if you're in your forties and your fifties, or
Speaker 1: you're guiding or know somebody is, this is the moment
Speaker 1: to get on top of this because the longer you wait,
Speaker 1: the harder it actually becomes. And if you're younger, don't
Speaker 1: be complacent because your heart can age really really quickly
Speaker 1: with lack of movement. In the end, your heart actually
Speaker 1: wants and needs to be challenged. It was built to
Speaker 1: respond and it responds to your environment. If you do
Speaker 1: very little, your heart age is super super quick. But
Speaker 1: if you actually do do the training, your heart will
Speaker 1: respond and it will get and can get younger, and
Speaker 1: you just have to give it the right kind of push.
Speaker 1: And I'll leave you with probably my favorite quote of
Speaker 1: any research journal I've ever read, from the Journal of
Speaker 1: Applied Physiology in twenty twelve by Professor Frank Booth, legendary
Speaker 1: exercise physiologist. He said, the human genome has not changed
Speaker 1: in over forty five thousand years. Their current human genome
Speaker 1: requires and expects us to be highly physically active for
Speaker 1: normal functioning, and that is certainly the case for the heart.
Speaker 1: Catch you next time.