 Dr. Andrew Steele, the Oxford-trained physicist turned longevity-focused computational biologist, recently sat down with Brent Nally of Lifespan News to discuss his book Ageless, the new science of getting older without getting old. We'll discuss the book and hear some interesting arguments from Andrew in this episode of Lifespan News. Towards the beginning of his book, Andrew explores the historical attitudes towards aging and the moral arguments surrounding it, and he did something that I found quite effective, but I might put a bit of my own spin on it as I recollect it. He asks the audience to imagine a world without aging, in which health and vitality are maintained. Now imagine the rise of a pandemic within this world, in which a disease that mimics the effects of aging begins taking over. People grow frail and weak and lose their physical abilities and mental capacities. Eventually, they become susceptible to other ailments and ultimately die. What steps might the inhabitants of this previously ageless world take to get this deadly disease under control? The answer is probably anything. Practically everything would be put on hold as the attention of everyone from nations down to individuals focuses on getting this problem under control. There may be some naysayers, those who believe that this disease is natural and therefore good, or part of God's plan. But would the inhabitants of this world listen to these arguments, or perhaps the ones that say that there are environmental or economic benefits to not solving this aging-like disease? It's unlikely. As Andrew argues in his book, aging is not a morally acceptable solution to any problem, and I agree. In Brent's interview, Andrew addressed why he made the switch from physics to biology, and explained why he thinks aging is such a pressing issue. It's been a sort of fascinating process for me because I started reading about aging biology toward the end of my physics PhD, so obviously it's not a natural obvious fit to go from physics into biology. But I just decided, you know, I was driven by the numbers, I thought this is the single largest humanitarian challenge of our time, and that's what I describe as in the book. And so I just had to change career. I didn't, you know, perhaps understand whether maybe I was approaching this naively as a physicist, and you know, there were some fundamental biological impacts, which is why biologists didn't seem to be as interested in as I thought they should be. And actually, basically, I changed career because of a graph, and that graph is the graph of how likely you are to die, depending on how old you are. So obviously your viewers will be very familiar with the fact that humans risk of death doubles every eight years. And if you just look at the graph, you know, look at what that entails. If I'm 36 now, my odds of death this year about were in a thousand. I quite like those odds. But obviously, if you carry on doubling something, we've all seen what happens with exponential growth when it comes to something like coronavirus. That means that by the time I'm 90, if there haven't been any advances in medical technology in the intervening time, my risk of death is going to be one in six. And that's, you know, life and death at the role of a dice. And that's just terrifying. And I think what the physics training really gave me, from a sort of big picture aging point of view, it just meant that I was immediately spoken to by that kind of very statistical argument. And it wasn't like people have often interviewed me and asked me, you know, did you have some terrible experience with death when you were younger? Or, you know, did you have some older relative who had a really awful aging process and it came down to some terrible disease that they suffered with for many years? But actually, you know, ultimately, although these emotional things have affected me throughout my life, the main thing that really drove me was just the scale of this problem. And so I decided, as I say that I had to work in biology to at the very least understand why this wasn't being addressed as much as I thought it should. Andrew then addressed arguments that say that aging is inevitable and that the laws of physics guarantee it. There are two ways you can answer this, right? The first is just a physics answer. And that's that if you state the second law of thermodynamics in full, what it says is that entropy will always increase. So, you know, disorder will always increase. Things will always fall apart, in essence, in a closed system. And what does a closed system mean? That means a system where you can't take energy in, you can't basically excrete, you know, send out disorder. And actually, of course, humans aren't a closed system. No living thing is a closed system. You know, if you're a plant, you're not a closed system because you can absorb energy from sunlight and you can use that to create food. And then once you've got that sugar, you can use that sugar and chemical reactions, which can then export some of that entropy into the surrounding environment. So, the universe as a whole, perhaps as a closed system, and so entropy will continue to increase. But as a life form living on a planet with a ready source of energy, then you're not a closed system at all. You can export some of that entropy. But actually, although that's a sort of a theoretical physicsy argument for this, I think the more compelling argument is just there are creatures that don't age. So, not only is this not a law of physics, it's not even a law of biology that creatures have to fall apart. And that's because, you know, we can use these entropy-decreasing biological mechanisms. And like, you know, you say that, it's just some kind of black box. You've got no idea what they really do. But if you look at something like a giant Galapagos tortoise, the reason that's there's a tortoise on the cover of my book is because tortoises are negligibly senescent. I mentioned right back at the start that humans risk of death doubles every eight years. Galapagos tortoises risk of death doesn't double at all. Once they become adults, their risk of death is flat with time. And so what that means is they've found a way to export that entropy. You know, whatever it is that's going on inside their cells, they don't have an increasing risk of death. They don't have an increasing risk of frailty or disease. They even say reproductively active up until old age, which I guess is something to aspire to. And what that means is that, you know, they're not aging in a very real sense. They aren't subject, seemingly, to this law of entropy. So clearly, I mean, it's not against the laws of physics because once you state the law in full, it's not a problem. And you might worry, well, you know, biology is complicated. Maybe systems, these things are always going to fall apart eventually. But the fact is, you know, it's not just tortoises. They're a fish. They're salamanders. There's even the naked mole rat, which is a mammal, so phenomenally evolutionarily close to us. These creatures seem not to age. And so if we can just, you know, work out some of their tricks and perhaps use science to import those into our own biology, then there's no reason why we couldn't be, you know, it's certainly something we should be aiming for because it's clearly something that's biologically possible. In the final clip we'll share with you, Andrew discusses buffs and the role that evolution plays in the biology of aging. That phenomenon is called negative senescence. It's not just negligible senescence. It's actually increasing in health with age. And from an evolutionary perspective, we might expect organisms like fish to do that. And that's because the traditional evolution explanation for aging is that once you've had your kids, you don't really matter anymore as far as evolution is concerned because you've passed on your genes. But that depends on the life course that evolution has chosen for you. So some fish have what's called indeterminate growth, which means they just keep on getting bigger. They keep on getting stronger as they get older. And in fact, in particular, the female fish, there's a wonderful acronym that the biologists have come up with for this, which is buffs, which is big old fat fertile female fish. And a huge majority of the reproduction in fish populations is done by this sort of handful of incredibly healthy old matriarchs who are just churning out the eggs. The eggs they produce are far greater in quantity, they're far greater in quality, so they're more likely to grow out to be young, healthy fish themselves. And that means that evolution has got an incredible incentive to keep these fish alive and healthy as long as possible. So evolution will custom design you an aging course, a lifespan, depending on the evolutionary reproductive strategy that you've chosen. And so these fish and various other species have clearly done that. These clips are just scratching the surface and the full interview covers so much more. We'll be posting all 50 minutes of it on the Lifespan.io YouTube page soon. When it's live, we'll have a link in the video description. You can also find Lifespan.io's review of Ageless on our website. Find Andrew or purchase the book in the links below. Please make sure to subscribe because we have so much more science content coming. I'm Ryan O'Shea and we'll see you next time on Lifespan News.