Hitting the Wall

hitting the wall

Here at Monstrow we don’t just love cycling, we also know and love the science behind it. In our Blog section you will find tips on training, group etiquette, and other interesting articles written by our knowledgeable staff.

“Hitting the wall” is a commonly used term in the endurance world. It is relatively common for athletes such as cyclists and runners to “hit the wall” or “bonk” during intense competition. The athletes’ speed slows and the legs and arms feel as heavy as lead. The athlete will frequently become disoriented and confused, as there is not enough available energy in the body to maintain basic processes, including thinking. The lack of available energy substrates causes the body to essentially “run out of gas” and therefore feels as if the body has literally run into a wall.

The primary source of energy used during prolonged periods of exercise, such as running a marathon or cycling 100 or more miles are carbohydrates and fats. Fats contain 9 calories per gram, and as such are more nutrient dense than carbohydrates, which contain only 4 calories per gram. So it would seem to make logical sense that the body would use mostly fats as its primary source of energy during those century rides, right? Unfortunately, fat metabolism requires significantly more oxygen and the delivery of energy is much slower than that of carbohydrates.

Carbohydrates are stored as glycogen in the liver and muscles. A well-trained endurance athlete can store 1800-2200 calories of glycogen in their respective bodies, which can last for several hours until that familiar “bonk” sets in. In order to avoid this common pitfall, a cyclist or runner must ingest energy in the form of carbohydrates every 30 minutes beginning approximately 90 minutes into the competition. Lets remember to eat on the bike so that we can continue to enjoy cycling hour after hour with a steady flow of energy!

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