Why Don’t Humans Live for More than 100 Years? | Physicist Geoffrey West | Big Think

Why Don’t Humans Live for More than 100 Years?
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Who wants to live forever? It’s a question that mankind has been asking itself for eons; how to extend our lifespans. Theoretical scientist Geoffrey West has an interesting proposition of we could do that. The more wear and tear we put on our bodies, he says, the faster they’ll break down and need repairing — sort of like a road. That might seem obvious to some, but West also suggests cooling our bodies and a steep caloric decrease in our diets to decrease metabolism. But would you want to live forever if you were freezing and starving? Join Geoffrey West as we sit down with him and ask about the fantastic possibilities - and inevitabilities - of human life.
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GEOFFREY WEST:

Geoffrey West is a theoretical physicist whose primary interests have been in fundamental questions in physics and biology. West is a Senior Fellow at Los Alamos National Laboratory and a distinguished professor at the Sante Fe Institute, where he served as the president from 2005-2009. In 2006 he was named to Time’s list of “The 100 Most Influential People in the World.”

Geoffrey West is the author of Scale.
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TRANSCRIPT:

GEOFFREY WEST: Since metabolism underlies the way we live, the way any organism lives, because it is the way energy and resources are being applied to cells, you can determine, calculate many things about organisms, about their growth patterns, how they grow, how long they take to mature—and in particular one that concerns many of us, and that is: how long we live? What determines our longevity? And, in fact, that’s what got me into this work originally was I became very intrigued in my fifties about the phenomenon of aging and of dying that I became more and more conscious that things had been changing in my life in terms of my body and my physiology. And that already I’d had friends die. And so I became intrigued as to “what is that?”

And I also became intrigued very much as a physicist not asking what is the mechanism and the systematics about aging and immortality, but the very question “what determines 100 years for the lifespan of a human being—why is it a hundred years, not a thousand years or a million years?" And also related to that, "why is it that a mouse, which is made of pretty much the same stuff as we are—we’re almost identical really in some kind of coarse grained level looking at things—how come a mouse only lives two to three years? So what is determining all this? And if you have this theory of networks underlying these scaling laws, manifesting themselves as scaling laws, you first ask: is there a scaling law for lifespan?

So this is work that had already been done by many people; was to look at lifespan as a function of size, for a bunch of mammals in particular but organisms in general, just as we looked at how metabolic rate scales across these animals. And what was discovered, what had been discovered was that lifespan also increases following these quarter power scaling laws—that it increased systematically. The one difference by the way, and maybe I’ll say a few words about this in a moment, is that there’s much more scatter among the data for lifespan compared to things like metabolic rate. So even though there is a kind of predictability—that is, you give me the size of a mammal, I will tell you on the average how long that mammal will live—there’s much more variance around that number than there is for saying “you tell me the size of a mammal, I will tell you what its metabolic rate is and what the length of its aorta is, how many children it should have” and so on, where there’s much less variance. The variance is much tighter. Lifespan has much more variance.

Now where does that number come from? So you have this theory that the scaling of metabolic rate and these many other quantities—and by the way there’s probably 50 or 75 such measurable quantities—these are determined by the constraints of flows in networks such as the circulatory system. So one of the things you immediately realize about those flows is that they are what we call “dissipative,” which simply means they involve wear and tear just as, you know, outside in those streets outside this building there’s a lot of traffic going back and forth on the roads and those roads wear out. They have to be repaired. The roadways have to be repaired and the subways have to be repaired.

Read the full transcript at https://bigthink.com/videos/geoffrey-...