What does a bonk feel like?

Title says it all. I think I may have bonked before, but I’m not sure. I only know the term, but not really sure what the signs and symptoms are. I understand everyone may be different, but it’ll be interesting to know how you know you bonked.

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You don’t “think” you’ve bonked. When you “bonk” you know it.

I did it once in a triathlon, and once on my very first long ride.

Imagine putting your bike in the easiest gear, on flat ground, with the wind at your back – and barely being able to turn the pedals.

It is the feeling of becoming totally unglued. Totally.


I’ve never bonked. I’ve “hit the wall” once, on a half-century, but I was still able to fight my way back home.

I have no idea what it feels like, first-hand, but I imagine it looks like this: https://www.youtube.com/watch?v=xSZlSaPJAdQ

EDIT: In other words, if you were to bonk, I imagine you would be completely useless. Like, falling off the bike, collapsing into a heap.

There are probably different degrees of bonking. I have never “fell off a cliff”, but have had a gradual erosion in performance where my capability was probably reduced by close to 50% - or at least it sure felt like that!

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Agree, you KNOW when you’ve bonked…I’ve done it maybe 3 or 4 times in 20 odd years and had to stop on the side of the road multiple times on a death march home, once had to call my wife to come and get me


I thought I had a “small bonk” once when I went from feeling in the best shape of my life to absolutely no power after one corner.

But it appeared to be mechanical issue, didn’t tighten my back wheel properly, luckily I didn’t crash on the descents.

This is what it feels like. When it happened to me the first time I didn’t understand what was happening. I could barely hold myself up on a bike. I made it to a gas station and bought a Gatorade, and felt strangely better – but didn’t know why. That Gatorade sipping got me another half mile and the wheels came off again. I could barely hold myself up. I couldn’t think either. I felt lost.


I don’t know if this was a true bonk (and therefore, some would argue that it wasn’t), but I remember a day before I knew anything about hydration or fueling, I went on a 40 mile ride on a very hot day with one water bottle and no food. I made it back to town, which is about 2 miles from my house. Those last 2 miles seemed so insurmountable that I had to call my wife to come pick me up. It was the worst I’ve ever felt on the bike.

You know when you see marathoners or triathletes wobbling down the road like they are drunk and collapse unable to get up on there own, that’s a bonk.


Haven’t bonked but hit the proverbial wall on my first metric century ride. Last 20 or so kms and I just couldn’t think straight. Bad posture, bad form, you name it. Couldn’t get the heart rate up as my legs couldn’t turn over 90rpm

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Okay, so that time when I was trying to do some threshold intervals and halfway through the workout I felt horrible pain down the back of my legs and had to drop to doing a zone 2/3 ride instead probably wasn’t a bonk? At the time, I thought it felt like a nerve pain, like my sciatic nerve was being compressed from my saddle, but it wasn’t happening beforehand, nor did it happen on the following ride.

So another question for some of you who have mentioned bonking…what caused your bonk if you know?!

Not sure if this qualifies as a bonk, but I once began to lose peripheral vision, balance, and got shaky all over (in a really short amount of time) in the middle of a long, under-fueled ride. A quick stop at a corner store, energy bar and sports drink helped correct it enough to get home. Not fun at all.

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SEE @DaveWh comment below.

One of the most famous examples (she cannot walk straight). Not sure how she felt. But this is what it looks like:

We understand a lot more about fueling these days. These days, when most ppl say “bonk” they mean what @DaveWh said. If you were in the state she was in on your bike it would be very dangerous.


For me, it was definitely: A) dehydration, B) insufficient fueling, C) excessive heat, D) pushing my physical boundaries (probably in this order).


Yes, these 4 factors although the order was probably different for me. My biggest bonk was doing the West Maui Loop as a flatlander with an FTP of about 100 and the bike handling skills of a 2 year old. Luckily I eventually made it to a pull-out with a little food van where my husband stuffed me full of soda and banana bread so that I could get back to the bike shop where we had left our car.

My other bonk was on the Half Dome. I just slowed to a crawl and every step felt like so. much. effort.

I was about 60miles into a 100mile “fun ride”. I was fairly new to centuries and didn’t know how to eat. I felt good early on and skipped some rest stops. I was starting to feel really bad, a little wobbly, and just barely made it to the next rest stop. I could barely move. I hung out there for almost two hours drinking heed and eating salted potatoes (this stop’s speciality). It was the oddest feeling I have had. No energy, somewhat incoherent, and loss of balance. I probably should have just hopped in a SAG, but I was determined to finish. I did.

If you have to ask, you’ve never bonked.

It’s like someone has sucked all the life force out of you and it takes every ounce of strength to just continue pedaling at an easy pace.

Zone 2 has an RPE of 10 when you are bonking.

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Happened good few years ago. It is when you need to stop every 100m to slow down the heart rate and deal with dizziness. When unable to stand upright. When 2km to home feels unreachable. I also remember excess of saliva and extreme hunger. Hopefully never again.

@runriderandi In other news you should probably have that sciatic thing checked out if it happens again. Not a bonk, but not awesome either.

I ended up ditching that saddle soon after because I was scared it would happen again. But looking back at it now, I was hoping maybe that was just a case of me bonking and maybe I could try that saddle again! Probably not the best idea…

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