What is the bonk?


In cycling terms, the bonk is the cycling equivalent of ‘hitting the wall’ in a marathon.

Also called ‘The hunger knock’, it will affect you physically and emotionally and make it very difficult to keep going.

The bonk is a funny sounding term for something potentially serious, outside of endurance sports it’s  known by its proper name of hypoglycaemia. It happens when you have exhausted the body’s glycogen stores, leaving you devoid of any energy.

Photo by Patrick Fore on Unsplash

It is a horrible feeling, running on empty, as if someone just removed your batteries!

The symptoms vary from person to person but generally, you will feel extremely weak and tired. You might sweat more than usual and feel dizzy or light-headed. every pedal stroke will be a masive effort, pedalling squares as Sean Kelly calls it.

Photo by Nathan Dumlao on Unsplash

You will probably also feel hungry, as it is a lack of carbs to burn that had your body feeling this way.

Your brain also needs carbs/glucose so you could feel anxious, confused and emotional. Your mind plays tricks and you might begin to ask yourself questions like “Whose stupid idea was this anyway? Why am I doing this to myself? I think I’ll just stop.”

It can be dangerous too, if you’re cycling on busy roads or in a large group and need your wits about you.

If you feel a bonk coming on, straight away eat some simple, quickly absorbed carbs such as an energy drink or gel. These will raise your blood glucose levels quickly.

Other suitable simple carbohydrates include jam sandwiches, fig rolls or similar or easy to carry sweets such as jelly beans.

Cyclists say, ‘if you’re hungry, it’s too late,’ so watch out for the early signs.

After you have eaten the simple carbs, stop for a while and have something more substantial such as a sandwich or energy bar. Give the food a chance to kick in before you take off again.

If you’ve dealt with the bonk early enough and caught it in time, you should be able to continue your journey, fully restored. Remember to keep nibbling on simple carbs as you go, to avoid a repetition.

To avoid the bonk in the first place, have a good breakfast before you leave the house. This means complex carbohydrates such as porridge, brown bread, fruit or rice etc. Tinned creamed rice is handy if you’re in a hurry.

But, no matter what you have for breakfast, it will be burned off within a couple of hours cycling.

So as you cycle along, keep eating small amounts at regular intervals. Set an alarm on your watch to remind you every twenty minutes or so if needs be. Energy bars, energy drinks, fruit cake, cereal bars, rice cakes or breakfast bars are all good sources of carbohydrates.

Don’t forget to adequately hydrate also, it’s just as important.


Keep her lit!