Here is the full transcript of interventional cardiologist Rohin Francis’s talk titled “The Greatest Medicine in the World” at TEDxNewcastle 2022 conference.
Listen to the audio version here:
TRANSCRIPT:
Introduction to Medical Magic Bullets
I don’t know if any of you have heard of medical magic bullets. It was a term actually coined over 100 years ago to describe therapy that’s so effective at treating a problem without causing loads of unpleasant side effects to the patient that it can be described as having the targeted precision of a magic bullet.
Infection is a classic example, really for the first time it allowed us to kill infection without half killing the patient, childhood vaccines would be others that have saved millions of lives safely and effectively, but both of those are not particularly new and in the lifetime of most people sitting here in the room there have been precious few magic bullets. There are medications that work of course, but the effect sizes are often more erratic and smaller than you might think or have been led to believe.
The Magic of Exercise
But there is one intervention which is sometimes overlooked and there’s mountains of evidence actually showing how effective it is at preventing all the biggest killers: heart disease, diabetes, high blood pressure, cancer, obesity, stroke. It’s been shown to be useful in managing conditions like depression, ADHD, anxiety, it can improve your mood, it can improve your bone density to reduce fractures later in life, it can improve the quality of your sleep, it can even offer that slightly less definable quality of just making you feel better.
If you haven’t guessed where I’m going with this, I’m of course talking about exercise. But you all know that exercise is good for you, you’ve heard that before, so I thought maybe I can be more persuasive today, instead of telling you that exercise is good for you, I thought I would show you why I think exercise is as close to magic in biology as we have.
Demonstrating the Body’s Response to Exercise
So please welcome onto the stage Julian, who is a fitness professional, and Dr. Ailey, who is a fellow cardiologist, both good friends of mine, who are going to give me a hand. So I said we all know that exercise is good for us, but yet 70 to 80% of Brits, we don’t get the recommended weekly amount of exercise, and I want to try and convey to you today what actually happens in the body when you exercise.
I mean sure you all know the heart rate speeds up and you breathe a bit harder, please try to control yourselves and keep your eyes on me. So what actually happens in the body, well it’s more than just breathing a bit harder and your heart rate speeding up, it’s actually a culmination of millions of years of evolution that have resulted in processes almost the entire body responds to exercise, and there’s a multitude, like an orchestra playing together.
And if you can see on the screen there, so Ailey is kindly scanning Julian, on the right hand side of your screen is the left ventricle, which is the main pumping chamber, there are four chambers in the heart, and the left ventricle is the chamber that pumps blood around the body, so we’re going to focus on that one today, and with that I’ll ask Julian to please start pedalling.
The Heart During Exercise
We’re going to try and get his heart rate up, this bike to be honest is pretty easy, so I don’t know how much exercise we’re going to make, because Julian’s an athlete, so this is going to be like looking in the engine bay of a racing car. But we’ve also just heard from an Olympic gold medalist, get those out of your mind, and let’s think about someone a bit more average, your average Joe, like me, will have a heart rate between 50-60 at the lower end, up to about 80-90-100 at the upper limit, it’s a range, everybody’s different, and with each heartbeat you’ll eject about 50, maybe 70-80 ml of blood.
So all of you sitting here today will have a cardiac output, that’s the amount of blood you’re pumping in a minute of about 4-5 litres, that’s what your heart is pumping every minute, unless some of you are finding this talk extremely exciting, I’m an optimist, and most people here can expect about 3 billion heartbeats in your lifetime, and of course your heart never takes a break, so you can see why I’m such a big fan of the heart.
Now we do most of our tests in cardiology at rest, because it’s easier, but actually our patients tend to get symptoms when they exercise, so we do try and exercise patients as well, not because we’re mean, but because we can get additional information. So we can do very clever things like measuring the amount of oxygen going in, the carbon dioxide coming out, and we can actually calculate what’s going on at a cellular level, or we can do something like this, which is to image the heart and visualise it as somebody exercising.
And the reason that’s useful is at rest the heart might look quite normal, but when you exercise someone you might see part of the heart that isn’t contracting as forcefully as the rest, suggesting that there’s a problem with blood flow. Obviously this is a heart in good shape here, but normally when I request this test at work I’m looking for a problem.
The Body’s Symphony During Exercise
And I mentioned this kind of orchestra playing together, so let’s think about what’s happening now that Julian started exercising, and this is where we can think back to our ancestors hunting prey on the African plains, or probably more accurately running away from a predator, and your fight, flight, fright response, the sympathetic nervous system is kicking into action, and catecholamines like adrenaline are being released into the bloodstream from little glands next to your kidneys, adrenal next to the kidney, adrenaline, that’s where it gets its name, and they are causing lots of changes to happen in the body.
So at rest you have division of blood flow to different organs reasonably fairly, but during exercise it’s overwhelmingly diverted to your oxygen hungry muscles, and big muscles like your quads, your glutes, your hamstrings, and of course your heart, are comprised of millions of individual muscle cells, each a symphony of electrical signals telling the cells to contract and relax, each pumping ions like calcium, sodium and potassium in and out at breakneck speeds, each with powerful filaments inside which shorten, and each part of bigger fibres which all pull together and can generate incredible power, and the source, the power for this power, is a little molecule called adenosine triphosphate, or ATP.
And your ATP stores are depleted quite quickly, you have a bit, but they’re quickly depleted, so other metabolic processes then start getting engaged, you will start then metabolising, you’ll break down glucose, glycogen, and fat, and produce more ATP. And where’s the ATP produced? In the cell, inside little structures inside your cells called the mitochondria, and I’m sure a lot of you have heard the mitochondria referred to as the powerhouses of the cell, and they really are remarkable organelles, they probably started as separate organisms millions of years ago that were subsumed into a larger cell, and have remained there ever since, powering the evolution of complex life on earth.
And of course all of that energy originally comes from the food you eat, and your body takes that food, breaks it down, makes it into fuel, powering all these little furnaces, generating heat, and that’s why exercise makes you feel hot.
Ventilation, which is the amount of air you breathe in and out, can go from about four to six litres at rest, up to about 100 litres a minute in a trained athlete. Actually, some of Catherine’s colleagues, ten years ago I scanned some of the British Olympic rowing team, and the numbers that these guys can generate are just out of this world. So the four, five litres at rest that I mentioned you’ll be pumping around your body, most of us can probably triple or maybe quadruple that, and some of these rowers were getting up over 40 litres a minute of blood being pumped around their body.
And this brings me to a magic number I want to tell you about. I’ve talked about magic bullets, I’ve got a bit of a thing for magic it seems, a magic number called VO2max, and your VO2max is a measure of the max amount of oxygen that your tissues can consume in a minute, and it’s corrected for weight and everything.
VO2max and Life Expectancy
And the reason it’s a magic number is because it’s strongly correlated with how long you live, and also markers of your quality of life. So the fittest humans in history have had readings up at about 90, whereas when you get down to the other end of the spectrum in the teens, then unfortunately without treatment your life expectancy is just a few years, And that’s when you’ll come under the care of a cardiologist like me.
And the rest of us have got numbers somewhere in the middle, the animal kingdom as it often does puts us to shame, racehorses will have VO2max readings about 200, huskies about 250, and some antelopes maybe as high as 300. Measuring your VO2max is difficult, you have to have a tight-fitting mask, a big machine that has to be calibrated regularly, you have to do it in a laboratory, whatever your smart device tells you that’s not your VO2max, that’s just a guess.
Resting Heart Rate as an Accessible Metric
And so it’s not really practical advice for those of you who want to take charge of your health at home. But there is another magic number that we all have access to, and you can all go home today and measure this, which is your resting heart rate. And that’s just the number of times your heart beats in a single minute. And it’s also correlated reasonably well to your life expectancy, with the lower numbers being better.
And I say reasonably well because obviously a heart rate of zero doesn’t confer immortality. But I do think it’s useful, and I tell my patients to track it, not because the absolute number is that important, I don’t want you to focus on that, but it can be a really powerful motivator for embarking on an exercise program. If you’re new to exercise especially, you can see your resting heart rate respond after just a few weeks of training. So I find it’s a really good incentive for people who are new to training.
Analyzing Heart Function with Imaging
Now, scans like this are not just offering us pretty pictures, but we can also do some very clever physics. We can calculate, measuring the speed of the blood, we can calculate the pressures inside Julian’s heart and inside the blood vessels, and we can then see how his valves are working and how his heart’s working. And we can increase the amount of blood we’re pumping through the heart in two ways, increasing heart rate or increasing how much each beat squeezes. And in a fit heart, normally your heart rate does most of that work going up.
But as we get older, the ability to raise your heart rate gets blunted, so we get more dependent on trying to get more blood in. Some people have quite stiff hearts, which have small cavities, so they can’t accommodate more blood. Maybe they’ve had long-standing high blood pressure. Other people have a different problem. They have baggy, floppy, enlarged hearts, so the problem’s not getting blood in, it’s getting blood out. And both of these things impair your ability to exercise. And what’s the best way to prevent some of these changes occurring to your heart? You guessed it, regular exercise.
There really is no way around doing this on a regular basis. And with that, I’ll ask Julian to start winding down and relax. So after exercise, Julian will start to feel the endorphins, those feel-good chemicals that give you that high after exercise. His blood pressure will come down to lower than it was before.
And all the changes we’ve talked about today are kind of the immediate effects of exercise. But of course, the magic happens long term. You have to do this on a regular basis, and these changes start accumulating and give you all those disease-fighting properties. And the message I want you to leave with today is that exercise doesn’t need to be triathlons and marathons.
It doesn’t have to be super intense. A lot of people are put off thinking that unless they do something really strenuous, they’re not going to reap huge benefits. And that’s not true. You can derive massive benefits without ending up a sweaty mess on the floor.
The Need for Societal Changes to Encourage Exercise
So I think it takes more than just individual decisions. If we really want to see exercise form an important part of our society, we need cultural changes, society-wide. I know the modern world of work has got us all sitting behind desks for hours at a time. And I mentioned evolution because people like to think about that as inspiration for certain ideas.
But I think there’s a lesson that we’re missing from our ancestors, that exercise doesn’t have to be something separate, removed from day-to-day life, like a chore. We can try and build it into our lives, and that requires all levels and everybody here and whatever fields you work in to think about how important it is. City planning, schools, a properly resourced healthcare system, government policy, and we need the changes to be inclusive as well, so as many of us can benefit from exercise without really even having to think about it. For me, as a cardiologist, exercise really is a magic bullet that has changed so many of my patients’ lives in really profound ways.
Tailoring Exercise to Individual Needs
But it’s not one size fits all. I really do think about it. That comparison I made at the beginning, I do think about it like another medication, like a tool in my drug cabinet. And you can think about it in terms of dose and frequency as well.
So it has to be adjusted. Some of my patients have goals of running ultramarathons. Some of them just want to lift up their grandkids or walk down to the shops. So find whatever works for you, stick to it, use this magic bullet, and reap a lifetime of reward.
Thanks very much, and thank you to Dr. Ailey and Julian as well.