Your Body: The Missing Manual

Chapter 11. Your Final Exit: Aging and Death

In the natural world, far from human society, life is nasty, brutish, and short.

We alone, of all species, have taken ourselves out of that environment and built a comparatively easygoing playground to live in. In our modern societies, we enjoy lives of relative contentment, free from natural predators and the daily fight for survival. The only wrinkle in this peaceful world is death—it keeps happening. Although death has always been part of life, now it happens with a twist. Today, death is less likely to come from a fight with a rival or a misadventure in the wild, and more likely to result from the slow erosion of your body’s operating hardware—a system-wide failure that gradually takes every organ offline.

This phenomenon—death by old age—is almost completely unprecedented, and it’s a concept that’s alien to every other species on the planet. We call it dying of natural causes, stubbornly ignoring the fact that there’s nothing natural about it. Being eaten by an alligator? Natural. Death from exposure? Just as ordinary. Consumed by parasites? Slowly starved over a long, bitter winter? Both perfectly understandable in the natural order of the animal kingdom. But to make it through these events to a time when the body simply runs out of steam, to see it succumb without a single external threat, its energy seeping gently away like a leaky balloon, is distinctly unnatural.

In this chapter, you’ll confront this riddle head-on. You’ll estimate ...