It's one of the most fascinating aspects of the natural world: certain shapes seem to repeat themselves endlessly, on small and large scales. The branches of a tree are very similar to blood vessels. The largest mammal, the whale, is an XXL version of the smallest, the shrew. Recent research they even suggest that the structure of the human brain resembles that of the entire universe. Nature "reuses" its most successful forms.
The theoretical physicist Geoffrey west from the Santa Fe Institute in New Mexico addresses fundamental questions in physics, and there are few more important than this: Why does nature continually reuse the same shapes? West explains that these "criteria" of nature are nothing more than "the universal mathematical and physical properties that make an organism viable and allow it to develop and grow." From this insight, West deduces a series of factors that could lead to incredible discoveries about the functioning and improvement of life. And what does the pill have to do with it? I'll get there.
I think that the reuse of the same forms is one of the most remarkable properties of life
Geoffrey westSanta Fe Institute
Larger scale, energy saving
There is a direct and surprising consequence that arises from the deepening of the reasoning made by West. It's about energy consumption: we might expect the size of an organism and its energy needs to scale by the same amount. For example, an organism twice the size of a mouse would need twice as much energy (food). Well, that's not the case. Scaling this pattern upward, it turns out, consistently confers a saving of 25% in the amount of energy required. An organism of double size it doesn't need 100% more energy, only 75%.
This energy “saving” means that larger organisms live longer, West says. This is because the body's internal networks, requiring less energy, consume 25% more slowly. West compares the effect to a road: it tends to wear out more and more with traffic. Less traffic, less wear. Larger organisms “consume” more slowly and remain viable longer. Yes, but the pill? A moment.
A pill to lower the body temperature
To extend human life beyond its roughly 100-year span (barring accidents, abuse, and genetic bad luck, of course) West says there are basically two ways: Either you reduce wear and tear, or you increase repairs.
Reduce wear it means reducing the amount of energy our networks have to process, lowering our metabolism. (This explains my inner question: “if larger organisms live longer, why does a turtle live longer than us?”. The turtle is smaller, but has a much slower metabolism). West notes that eating less could accomplish this, but experimental studies haven't shown that reducing calorie intake actually has much of a metabolic effect.
Another option has to do with one of humanity's most distinctive characteristics. Human beings are homeotherms: it means that our body temperature remains substantially constant, little affected by the external temperature. This dissociation with the outside temperature has been a great advantage for survival, allowing us to live in different climates, but it carries a high metabolic cost.
More than tall. Keeping our bodies warm when it's cold and cool when it's hot requires a dramatic increase in metabolic rate. With this in mind, West imagines a pill that lowers our body temperature (and therefore our metabolic rate). A pill capable of reducing the wear and tear of our networks and allowing us to live longer.
A “thermal” pill: would it work?
Compensating for the thermal difference impacts our internal networks, West says, because chemical reactions inside our bodies react exponentially to temperature. “A small increase in temperature exponentially increases the metabolic rate.” (This, West points out, is why the one or two degree increase in global temperature caused by climate change is so biologically significant.)
Developing a pharmacological solution, a pill that helps us regulate the temperature could be able to solve two problems: that of longevity and that of the effects of climate change.
