What is bonking?
 

I keep seeing some posts that mention bonking. Is it some kind of mid-biking activity that's really fun? Trying to figure out if I should bonk but I don't know if it's something you do alone or in a group activity or what. Can someone please be a sweetheart and fill me in? I ask at the risk of sounding like a dork to the professionals here..but I have an eagerness for learning. >.>

-Jen

Hi PanzerGirl!

I'll take a try at this, but don't bet money on my answer...

"Bonking" is when your body has exhausted all available carbohydrate energy. Bonking typically happens suddenly, leaving you feeling utterly exhausted. Your body can't keep supplying your muscles, so no matter how hard you "will the body to go," you just can't continue (except at maybe a radically reduced pace). Obviously, I don't know the scientific explanation for bonking, but I've certainly experienced it.

If I understand correctly, the potential for bonking is why racers tend to carry carbohydrate-enriched drinks and "power bars" on their rides.

Now that you've had the "layman's explanation," I'll let wiser souls than I give the details (and correct any of my misconceptions).

Thank-you so much! The way some forum posts talked about it in a vague manner, I almost wondered if it was related to boinking in any way. :)

It's a generic term for what Rolls Royce refers to as "a failure to proceed"....
After a couple hours you can use up your carbs, and that is the common bonk.
I am real good at depleting electrolytes, and that ain't a bed of roses.

Basically, as your exercise stretches out past an hour, you need to think about
nutrition. Your body needs stuff like carbs, water, electrolytes to keep pumping.
While it can get complicated; the basics are quite simple. Drink early and often.
Have a snack once in a while, and if it's hot, have a sports drink that has sodium and potassium. If I am stuck drinking gatorade or powerade, I will often mix them with water to cut the sweetness, and than add a teeny tiny dash of salt to
bring the sodium level back up.

For me, the bonk hits about 3.0 hours into a ride of good intensity, like lots of climbing at LT or intervals. It comes on within about 15-20 minutes. One moment I'm fine and cranking along at 20-22mph. Then I gradually start feeling cold and clammy, like I'm sweating too much and cooling off too much. Then the legs start feeling weak, not in pain or sore, just feeling heavier and weaker. Eventually the vision dims a little bit, my ears feel cold, my body feels cold, and no matter how hard I push, I can only manage 8-10mph. I also start scanning the ground for scraps of discarded food to eat. I've heard of people licking candy-wrappers to scrape off little bits of chocolate and sugar... :eek:

The way to avoid this is to eat 200-300 cal/hr of simple carbs for maximum digestion/absorption rate (complex carbs are only 100-150 cal/hr). Along with adequate water and electrolytes. This will won't match the burn rate of 500-800 cal/hr, so eventually you will bonk after 6-8 hours at a brisk pace. To go farther and longer, you'll have to slow down to lower the burn rate to 400-600 cal/hr, and this will also increase the percentage of energy delivered from fat-metabolism as well. At 400-500 cal/hr burn-rate, you can pretty much even out your maximum-digestion rate combined with fat-metabolism to ride indefinitely. :)

Yup. I've found the 3 hour time frame to be significant also.

We could only wish... :p

I use an industrial product called "Sqwincher." It has a balance that my body likes AND it's CHEAP!

Can you boink and bonk at the same time? :D

I remember the first time I encoutered "bonking out". It was back in the mid 70's while I was training to run my first marathon. I didn't know what was going on, and thought that I was becoming seriously ill. I stopped at a 7-11 and drank a Slurpee. Almost instantly I was feeling better.

What a way to go... :D

Your brain runs on sugar, and to make sure that it has enough sugar, it has a protection mechanism built in. If the amount of reserve sugar in your liver runs low, your body basically shuts down your muscles so that the brain can have enough sugar to proceed (there are mechanisms to make sugar when you don't have any, but they don't make very much).

That is bonking. Interestingly, it's related to the amount of sugar that you have in your liver stores - you can have sufficient sugar in your muscles, but there's no pathway to get that back into the bloodstream.

Typically, bonking happens when riders either don't have enough food or forget to drink. It has a very quick onset - you can go from feeling good to feeling rotten in the space of 5 minutes. At that point, your performance goes *way* down - you go from riding easily at 17MPH to having trouble to go 12 MPH.

The timeframe depends upon how much glycogen you had stored, when you ate last, how hard you were working, and other factors.

The only treatment is to get some sugar into your body and take 20 minutes or so. Any sugar is good. That will let you get home, but you will still be miserable.

Note that if you have friends who are from Austrailia or New Zealand, "bonk" means something totally different to them...

I would think the boink would come first.

Well it could be with a right company. :p Alas on these forums it reffers to all those nasty things that happen when you go too hard without eating enough. Had it happen to me three times. One was because of the heat. I couldn't even stay on the bike. All were 4+ hour rides. Had to get off the bike, or risk crashing. :( Moral of the story, eat before you feel you have to, drink before you are thirsty.

During the bonk your body has run out of stored carbohydrate in the blodd, muscles and liver. There are two other sources of energy, stored fat and muscle tissue itself.
During the bonk your body is switching over to fat metabolism. It is quite possible (though unpleasant) to ride through a bonk and carry on riding for a few days depending how much fat you carry around.
The switch to muscle metabolism when you run out of fat is altogether more painful, leaving your arms and legs aching. This switch is so rare that it doesnt have a common name.

Is burning muscle called ketosis?

It would have to...ya can't boink if ya bonk.

Bonking while Boinking.

Time for some Goo?

HER: Honey, what's that?
HIM: It's Goo!
HER: Hmmm, never tried that for sex, you're kinky.
HIM: Actually, I was just gonna eat it.. hmmm...


Actually, you're always burning fat, but it requires carbs/glucose at the same time to burn fat. When you run low on glucose, fat-burning is turned off and it uses muscle instead. Conversion of proteins to acetyle-CoA through gluconeogenesis is highly inefficient and requires a net-input of energy and is a very, very slow process.

Ketosis is fat-burning. Here's a good summary site that shows the various pathways of energy-production: Metabolism - Carbohydrate, Protein, Fat, Cholesterol. About 3/4 of the way down the page is chart showing all the pathways. Note that input of ATP from glucose is needed to start the fat-burning pathway.

How cute is that?

Thanks, that was a very charming way to start my morning! :D

Some of us can even Boyink, boink and bonk at the same time...:D

Bonking is a common cycling term for a variety of symptoms caused by low blood sugar. One is said to have bonked if they experience:


Extreme Exhaustion
Mental Confusion
Hallucinations
Being "Out of it"
Passing Out

A cyclist can experience any or all of these symptoms during the course of a bonk. The brain runs entirely on sugar. The blood stream has sugar for the brain, but only enough to last a few minutes. The sugar supplied to brain comes from the liver's production of sugar. When the liver is deprived of the energy required to make or convert sugar for the brain, bonking is the result.

Bonking is not just something that happens to new cyclists or even cyclists on long rides. Anyone can bonk at any time. The key to avoiding bonking is to continuously eat during a ride.

Some experts recommend eating something every 15-30 minutes depending on the length of the ride.What you choose to eat does not matter. It can be a sugar food, salty, anything... Some riders choose to eat fresh fruits or nutrition bars. The key is to eat. Try stuffing something handy into your jersey pockets or seat pack. It can make a world of difference in not only your performance, but your mental ability to ride.

It's muscle-glycogen not blood-sugar that's the issue. You can eat a big breakfast an hour before a ride and get an insulin-spike with food-coma right as you're starting the ride. You're gonna feel sleepy and sluggish, but your muscles will be fully packed and ready to go. You're 3-hours away from bonking even with low blood-sugar.

Unfortunately, muscle-glycogen concentrations aren't easy to measure without a biopsy and blood-sugar may be used as a proxy indicator somewhat, but you have to measure it over time and watch its rate of change relative to food ingestion and exercise levels.

That 3 hour onset is a funny thing. I'm 58 and mainly ride to keep trim. I'm riding way less miles than many of you and I ride a flat, creekside trail. There is maybe 15 feet of elevation difference from one end to the other. If I relly push it and go the full 22 miles, I arrive home feeling fine. About two hoiurs later; bonk. I get knocked flat with lack of energy. A tall glass of orange juice really helps. bk

That's your body sucking all the glucose it can extract out of the blood to rebuild the glycogen supply that you burned up in the muscles. Best recovery is in the critical 20-30 minutes immediately after a ride. Eat a 4:1 carb-protein mix of about 300-400 calories followed by a normal meal within a couple hours.