The 5 Emotionally Charged Stages of Bonking on the Bike

One of the less desirable inevitabilities of life as a cyclist, “bonking” ranks among broken chains and multiple punctures in the pantheon of “it’s not as bad as that day when I—” stories.

The human equivalent of a kite reacting to a strong gust of wind, bonking is that ride-ending feeling that takes you from flying high to falling hard in a matter of minutes, your tank drained dry and your muscles shot. There’s no solid scientific definition for bonking, says exercise physiologist Sean Burke, founder and head coach of Crank Cycling, but “it’s most likely linked to glycogen depletion.” High-intensity exercise requires carbohydrates like glycogen, and once the glycogen in your muscles is used, you have to rely on fat for fuel. Energy from a fat molecule is released more slowly than from a carbohydrate molecule. “That means less power to the pedals,” Burke says.

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Bonking seems simple enough to avoid: You need to put fuel into your body to get energy out of it. But sooner or later, every cyclist will find themselves weeping into a pile of candy wrappers and wondering what they did wrong. For the uninitiated, this tearful tango has five simple stages. If you look back hard enough, you’ll see how you danced through all of them.