Bonking, been there, done that, did not like the feeling. Would like to never repeat. Old people on bicycles with big baskets filled with their weekly shopping on their handlebars were passing me. Arghhhh!
Bonking is the feeling of being out of gas, where your legs have turned to jelly, and the body is just not right with the world. If you were a runner it would be called “Hitting the Wall”. A doctor would say you had low blood sugar (read fuel). It also means you haven’t taken in enough carbohydrates and have exhausted your body’s glycogen stores, leaving you with abnormally low blood glucose levels. Your body can only store enough glucose (in the form of glycogen) to last you 90 minutes of moderate exercise. Once your glycogen is gone, your body will start using fat for fuel, which is released more slowly than a carbohydrate. That means you will be getting less power to your pedals!
So, what should you do if you feel a bonk coming on?
Our video is from our friends across the pond at GCN. This video times in at over 6 minutes, but it does go into more depth on longer ride planning and pacing strategies. It even has "Bonk Graphs" and a must-see pizza delivery mechanism at the 2:25 mark.