B is for Bonk


Although I’ve been pretty much on track for my monthly mileage target for March, I decided I wanted to try to ride 100km today, as I’d not done a 100km ride since January. So last night I mapped out a ride using Bikehike and uploaded it to my Garmin this morning heading much further south than normal, using roads that Malcolm had introduced me too on a couple of previous occasions.

It was an absolutely beautiful day but I had a great deal of trouble making myself leave the house, I could have easily sat at my desk all day and in fact did for an hour and half longer than I’d intended too.

Once I got out on my winter bike (taking it was an excuse to ride slower) I felt good although I had my first hunger pang – just a little one within 20 minutes of beginning the best part of a 4 hour ride and I should have paid more heed to it but I’d started the ride and had therefore committed myself. 



In fact the first hour went really well and I covered 30km including a category 4 climb which I rode just a fraction under my best time. After two hours I’d averaged 29kmh and was well over half way through the journey and had climbed 500m or so. I was riding well. In fact, I was riding the best I have so far this year. The sun was shining, the countryside was stunning and there was even the occasional other roadie out who was also happy to smile and wave.

All was well in my cycling world.


I’d even managed to take a few photos including some terrible attempts at Pandas – the best one is in this post above and as I got well into the second more challenging climbing segment of the journey my hunger pangs started to turn into a dreaded bonk.

For those of you who’ve not experienced the famous cycling bonk, it’s when you’ve typically not eaten or drunk enough while your riding and you literally hit a wall and lose almost all of your energy. The only way to fix it is to refuel – but in most cases when it happens you’re out on the road somewhere and it’s difficult to fix this. It’s a hero to zero situation as you fairly rapidly lose almost all energy and generally just want to get off the bike as soon as you can. 

I reckon it hit me at about 80km and before it hit properly I thought I was just slowing up a bit from fatigue more than anything else. It really hit me once I’d finished all my climbing and was doing the last small crest into a head wind. My speed crashed and I found myself having to change down to the small ring because of a 15-20kph head wind and my speed dropped to around 15-17kmh where I’d been doing 30ish before. On the following descent I found myself changing down gears descending into the headwind and I knew I was in trouble. At least I was able to descend for a while. 

On the last Strava hill segment of the ride not long before Groombridge I recorded my slowest ever time. Considering I’d be recording virtually best time in the first half of the ride, this confirmed the bonk. I had orginally been aiming to complete the ride in 3hours 30 and had been on track but in the end I worked very hard to get back in 3hours 45 after losing that extra 15 minutes in the last 20 kilometres.

I was absolutely shattered by the time I got home and rushed inside to down a recovery drink, an energy drink, biscuits, yoghurts, sandwhichs and anything else I could get my hands on.

I had eaten an ok (not a great) breakfast but that was nearly 3 hours before I left for my ride. I took one small banana as food for a 100km ride and two 700ml energy drinks. I should have eaten a bigger – perhaps a second breakfast 30minutes before my ride as well as some energy bars or gels (I’ve run out). 

It was still a really good ride, not least because the day was a cracker and for the first time this year I really felt a hint of form. Like my tweet said – I rode well for 80km today – just a shame that it was a 103km ride. Still, bonks happen – it was my first for quite sometime and hopefully experiencing it today will make me ensure I don’t again for a while.

I’ve just re-ordered my energy foods/drinks this evening.


Thanks for reading