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WE NEED TO TALK ABOUT BONKING. Quiet at the back! Sniggering aside, the concept of bonking is a familiar term for cyclists but what does it mean? Some might say fatigue and sudden energy loss, others might talk about the desire to turn back and head home, cutting short the training ride or hitting the wall. For me, it means literally going bonkers, but before we head over to Wikipedia to check it out, I thought I’d just talk about my personal experience of this phenomenon. The first time was indeed memorable! I had just picked up my first road bike from the LBS and had decided to go for a spin. That was a seven mile, hilly spin without water, no padded shorts and in the height of summer. Ouch! When I eventually returned home I remember standing on the doorstep looking up at Charlie, my husband, and asking; whose is this bike? Is it mine? Why have I got a bike? The alarmed look on his face was nothing compared to the state of terror I was experiencing. I had only ever lost the plot like this when drunk and I assure you I was stone cold sober. Fast forward a few years and again I found myself standing by the side of the road on a 200km hilly Audax in Wiltshire, once again asking myself who am I and where I was? All I remember is shaking and needing to simply stop and get off my bike. I recovered myself enough to head to a cafe and sit down. I drank three huge teapots of tea with lots of spoons of sugar. I felt awful but as the tea washed down I began to recover. A recent trip onto the trails with a couple of MTB friends was another good example. This time I had the foresight to alert them to the fact that I needed to stop and consume some food before the ‘Bonk’ got the better of me. I worked out that this bonk was because I was out of my comfort zone, nervous and breathing from my upper diaphragm so effectively going hypoxic with the exertion. Food and rest and I was ready to ride again. Maybe I was getting the hang of this strange physiological crash. But no, it happened again today! There was, sat on my turbo with a workout in front of me that said “Give it all you have” so I did, and a little bit more. An hour and fifteen minutes later I ‘woke’ to find myself attached to my bike still pedalling. I knew I had pushed beyond the edge of my envelope and that was enough intensity training for today! I stopped cycling and sat down to recover. So what is with the physiology of bonking? Well according to my research, when you exert yourself in HIIT or cycle for a long distance – your body’s glycogen stores can become quickly depleted. This often results in overall physical exhaustion but, because your brain also relies heavily on glucose to fuel cellular activities, this depletion of glycogen affects your brain too, causing mental confusion. It would seem that for me the exhaustion is not the prime indicator of bonking but being able to talk and think coherently probably is. Some might argue this has always been my problem! The upshot is I simply underestimated my workout today and the amount of energy needed to complete the session. So as I ramp up the training after the winter base miles I will be a tad more mindful of just what I am eating and what is needed energy wise to fuel my rides and complete my training workouts. Food for thought!

Photos by Sheila Woollam.


Sheila picked up a bicycle nine years ago and rode the Camino from Canterbury to Santiago de Compostella. That’s quite a first ride but since then she’s ridden unsupported around Iceland, from Tunbridge Wells to Budapest, completed the London-Edinburgh-London event and competed in the 2018 Transcontinental, riding 4,202km / 39,352m in 21 days. 2019 saw Sheila winning the long route in the Race around the Netherlands, and after a few weeks of rest, Sheila competed in the Pan Celtic Race around Scotland, Ireland and Wales placing 2nd Solo Female on the long route. What’s next? Watch this space for updates! #TCRNo6cap127 #RATNCapNo88

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