So, that's what it's called...

THE SCIENCE BEHIND BONKING

When your body stalls mid-run, it's called bonking. When scientists debate the causes, it's called a food fight. Here's everything you need to know.

By Paul Scott (PUBLISHED 03/01/2004)

Chiang Kai-shek is said to have received news of his army's mutiny while still in his pajamas. Chances are you will be equally unprepared for the mutiny of your own body--in other words, for bonking. We're not talking about the mere cramping of a calf, or the everyday slowing caused by lactic acid build-up, or the deep muscle pain sometimes caused by downhill running.

Marathoners used to call bonking "hitting the wall," but it's actually a bodily form of sedition. In some form or another, it becomes a collapse of the entire system: body and form, brains and soul.

Consider the muscle-glycogen bonk, where the brain works fine but the legs up and quit. Then there's the blood-glucose bonk, where the legs work fine but the brain up and quits. Let's not forget the everything bonk, a sorry stewpot of dehydration, training errors, gastric problems, and nutrition gaffes.

And then there's the little-purple-men bonk. "After about 20-K, I started to see little purple men running up and down the sides of these cliffs," says Mark Tarnopolsky, M.D., who wears hats as both a leading sports nutrition researcher and an endurance athlete. "I knew it was an hallucination, but I stopped in the middle of the race to look at them anyway," he says. "It was kind of crazy."

If you have run a distance race, chances are you have already become an aficionado of the bonk. You remember how your form held until you hit mile 18 and your feet turned into scuba fins. How your motivation held until you faced that last hill and became preoccupied with the idea of lying down on the pavement. Or, if you bonked thoroughly enough, how you began to see beings that belong in Dr. Seuss. And you thought sports nutrition was dull.

And now, the field is undergoing the scientific version of a food fight. The sanctity of carbohydrates has come under question. Endurance athletes are rediscovering protein. Products are making new claims, nutritionists are taking sides. And we haven't even gotten to the reasons why many runners act so weird about food in the first place. But in essence, the science of bonking comes down to 10 laws. If you learn them, you won't merely be on the cutting edge of sports-nutrition science, you may never bonk again.

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