The natural history of running

My college friend J.-J. and I must have been at the far unlikely end of the spectrum of those who could be expected to pick up a truly obsessive sport habit later in life - the main things I remember us doing are smoking lots of cigarettes and drinking to excess and having some very good conversations about the satirical novels of Evelyn Waugh!

In fact, we have recently reconnected on Facebook, where I spotted his Ironman finisher's photo, and since then we have been having some very good obsessive endurance sport back-and-forth exchanges, literary and otherwise.

(He points out that endurance sport is in many respects a literary or philosophical phenomenon as much as it is a fitness-related activity!)

He recommended that I read Bernd Heinrich's Why We Run: A Natural History, and I found it utterly mesmerizing. The opening stretch of pages is perhaps slightly too lyrical metaphysical for my tastes (I have never been able to read Thoreau seriously, or the more fanciful pages of Emerson!), but it develops into an absolutely wonderful book with all sorts of fascinating reflections on physiology and distance running - the kind of thing a highly original zoologist might indeed come up with as he tried to figure out how to train and race best at distances long enough that there was very little prior data to examine.

"[T]o the fawns of pronghorn antelopes and other ungulates that require speed to survive," Heinrich writes (summarizing the research of John A. Byers), "play is fast running that may be interspersed with twists and leaps. It has long been argued that such exorbitant, apparently useless expenditure of energy is a survival cost. Contrary to this supposition, Byers found that those pronghorn fawns who played more had a greater chance of surviving the first month of life than those who played less."

Playfulness in this context is an advantage, and Heinrich in a sequence of middle chapters moves through a number of different animals, each of which offers insights into different aspects of human running physiology.

Here he is on the camel, whose hump of back fat serves as a heat shield from the sun and allows the less-insulated belly to assist with heat loss:

Part of the camel's secret is just plain toughness and the ability to survive desiccation. We're near death is we lose water equal to about 12 percent of our body weight, but camels can survive body water loss of 40 percent of body weight. After being dehydrated, a camel can ingest 20 to 25 percent of its body weight in one drinking bout. As in humans, the ingested water reaches the blood plasma from the stomach relatively slowly, requiring about an hour to attain a 25 percent equilibrium. But unlike humans, camels tolerate blood dilution to an extent not tolerable in other mammals. Our blood cells swell and rupture in dilution, and we can become very ill and even die from water toxicity if we drink too much liquid, especially when it is dilute (without salt or sugar) and therefore absorbed more quickly.

And when it comes to smoothness of stride, high-speed cameras have revealed that one champion runner is the American cockroach (Periplaneta americana, which

raises three legs at a time and keeps three on the ground. The first and third on one side and the second on the other are used as a unit. The roach moves using such alternate tripods. The difference between walking and slow running is simply the rate at which successive tripod steps are taken, although when really cruising, some cockroaches do something different. They spread their wings, shift their body weight to the rear, and become bipedal by running on their hind legs. American cockroaches can spring this way at some fifty body lengths per second. By that measure, they run about four times faster than a cheetah, the world's fastest land animal in terms of absolute speed.

What follows is a rather enchanting description of the All-American Trot, held annually at Purdue University, featuring cockroach footraces "on a custom-built circular track with racers coming from entomology department research stock." (Here's another report on the event - both descriptions note that the lumbering Madagascan hissing cockroach is harnessed to a miniature green-and-yellow John Deere tractor.)

Humans' elongated feet are much better adapted for running than the grasping digits of apes, and Heinrich speculates that foot size may be a significant explanatory factor in the difference between elite men's and women's running speeds, a gap which has to some extent resisted explanation. His thoughts on migratory birds and how they fuel for their feats of ultra-endurance are very effectively woven back into a discussion of metabolic issues and fueling for ultra-distance runs (the book is in part structured as an account of how he came to win the North American 100K Championship in Chicago in 1981).

At one point, Heinrich says of a run he logs, "It was not all out. I usually tried to keep a little back, so that willpower would accumulate, like a battery on a charge." The book is full of such insights, and the language - especially when it comes to matters zoological - is vivid and clear and particular. A classic of the genre. (J.-J., thanks for the recommendation, I hadn't even heard of it before you mentioned it!)