hubcyclist

Personally, I feel like people conflate bonking with fatigue. I believe we have the capability to store about 2000 calories in glycogen. I'm pretty well trained and for a long endurance ride I can burn 800 calories in an hour, someone newer would be in the 200 calorie range (if you're measuring by power/kj of work). So I suspect a lot of 'bonking' is just overextending one's capabilities and not a true depletion of fuel. I'd have to ride pretty dang hard to actually deplete my glycogen.

Flip Flop Rider

you remember fatigue

downtube42

After decades of being a normal cyclist, I was introduced to the world of ultra cycling and randonneuring. 24 hour races and rides longer than 200 miles changed a lot of my thinking about nutrition, hydration, pacing, cramps, and fatigue. I am just one data point, an experiment of one, but I do not believe I'm an exceptional athlete.

What do these words mean: tired, fatigued, bonking, exhaustion? Are they discrete things? What is that tired feeling I get after 30 hard miles, vs the tired feeling after 100? Why do i feel better after 40 miles than I do after five? How is it I can cramp up at 60 miles, but at 80 miles on the same day be rolling at 20mph? How is it i can get up after four hours of sleep and finish a 600k?

What I believe now is fuel trumps fitness, hydration trumps fueling, attitude trumps almost everything, and the need for sleep is what ends rides. My body can burn virtually anything. Food variety is good. Fitness determines speed, but fueling determines distance. Don't think so much, just feed my stomach what it wants. My job on a long ride is to take care of my mind and body.

Bonking? Forget the word. Hydrate, fuel, listen to your body.

Nessism

I can't speak for anyone else but to me bonking is real and clearly different from fatigue. It happens after a sustained high level of effort for more than 2 hours. I'm talking about riding with a heart rate within 15 bpm of the anaerobic threshold. The body can't metabolize fat/muscle fast enough to replace the glycogen that's being depleted at that level of burn. My brother is a marathoner and he's had the same problem during his first few races because he didn't consume any calories. Once he figured that out it's not happened since.

Edit: as mentioned earlier in this thread on the occasions when I bonked I chugged a coke because no energy type drinks were available, and was astonished by how quickly my body was ready to ride again. I went from feeling completely wiped out to being ready to push for home quite quickly. That's the beauty of sugar: instant energy. That's about all it good for some would argue though.

Russ Roth

That's just the minor language spelling difference in our Englishes; that's boink and not used much anymore that I've heard.

My own experience, fatigue is something that you can feel developing through the ride, the pedals seem harder to push, the hills seem steeper to climb, recovery at the top takes longer. But its something that steadily happens over any ride that approaches your typical limits or exceeds them. Bonking is much more rapid and drastic. Although I can't recall the number of times I've pushed myself to exhaustion, usually with someone's help, I can only recall bonking twice. Both times weren't even close to the limit of what I could ride, once was after only 30 miles at a time when I would ride 80 miles through the Catskills to spend a weekend with my grandparents, 30 should have been nothing. In both cases suddenly I just had no strength, just stop the bike carefully and lean heavily on the handlebars. Didn't even feel I had what it took to get off the bike, just straddle the top tube and sag on the bars. After 5 or so minutes I could start again but only towards home with no speed, no strength, and struggling just to do 8-9mph on flat roads. That's what I consider bonking.

rsbob 

Was at the first 100 of a 200 mile day (Seattle to Portland) when I started getting light headed and started getting tunnel vision. Had to stop before I fell over and quickly ate an energy bar. <- total bonk. Fortunately I was only 2 miles from a fully stocked rest stop with tons of food and water refills. Stuffed my face and my pockets and finished the 200 in 11 hours. Never made the mistake again of not keeping fueled

OP, bananas spike your blood sugar and then you crash unless you keep eating. A small but good balanced meal, fat, protein, carbs is a good way to start a ride and carry food with you if you get hypoglycemic. An easy one is a PB and honey sandwich or an egg, imitation bacon and toast.

canklecat

GCN and Dylan Johnson have covered this topic several times on their YouTube channels. Here's GCN's more recent, and among their more interesting comparisons between two recently retired pros. Conor eats nothing for the 140 km trip (but drinks as much water as necessary) while Hank eats whatever he wants.

And it's not just a casual long ride staying within the low effort range where Conor could rely solely on fat metabolism. They throw in some hard efforts and intervals that would normally demand a sugar boost from gels, etc., to keep going.

And Conor does blood glucose checks at intervals throughout the test.

The video refers to something I was unaware of in the 1970s when I was training: the short lapse between consuming sugar and resuming hard activity to avoid insulin spikes and subsequent hard blood sugar crashes. I recall one particular incident when I was getting ready for a 10 mile run, including some steep hills, with a Marine Corps squad (I was a Navy Corpsman and trained with them, same PT, etc.). I got to chow early and crammed a bunch of donuts, which I didn't ordinarily eat. But there was too long a gap between breakfast and the run. By that time my body had already overreacted to the unaccustomed sugar rush and I bonked hard during the hill run. That had never happened to me before.

I'd have been better off skipping the donuts. Or stuffing the donuts or other carbs/sugars in my pockets to eat during the run. But that wasn't a common thing during the 1970s, outside of cycle racing. A lot of what we were taught back then about hydration and diet for football, boxing, running, long marches and hikes, was completely wrong.

So while sugar is an essential fuel for maximum efforts, the timing is critical -- don't wait too long between consuming a sugar bomb and resuming the workout. Same with alcohol. Some folks find a beer, wine, champagne, etc., gives them an energy rush. But it's short lived and doesn't work for everyone. (Generations ago in cycle races, alcohol was the most common form of "doping" and some cycling organizations tried to impose limits on alcohol consumption, and finally banned it completely.)

Kapusta

The way I describe the difference is that fatigue is when the muscles are tired. Bonking is when there is just no fuel in the tank.

I can push through fatigue. Can’t push through a bonk.

Main thing for me is to keep calories coming in steadily and not waiting until I am bonking to eat, because at that point it seems like it is too late.

Also, I stay away from a lot of simple sugar when fueling up.

Grouperdawg

For what ever reason I can’t eat before any hard ride even a few hours, it jacks my stomach up and I suffer, it doesn’t matter what I eat. It makes no sense but my power and heart rate also support this. After a couple hrs of riding I will start to feel normal again and I’ll even watch my garmin performance go from a minus five to a zero. So I just stopped eating the morning of a ride. If I’m doing a century or something longer sometimes I’ll eat some peanut butter crackers or something light occasionally but i can go all day without anything, I have to have water though.

I’ve never bonked in the way most describe, it’s usually my legs that will give out where they are just so sore I can’t feel them when I’m at my limit

drlogik 

Typically "hitting the wall" or "Bonking" is when the glycogen stores in the muscles and liver deplete to a point where the brain just shuts things down. Fatigue is the warning signal that hitting the wall is coming unless you replenish the body. This "generally" doesn't affect a cyclist just out for a regular ride. It generally is when cyclists do very long and intensive rides like a century, but each person's physiology is different.

When I was competing in cross country ski marathons (usually 50k to 55k races) in 1979 and through the early 1980's, often times in sub-zero temperatures wearing a one-piece full-length Lycra suite, I hit the wall two times. The first time I passed two feed stations to keep up with the lead group, wrong! By the next feed station I was about 30k's in and barely hanging on by a thread and told my mind, "you can do this". About 3 or 4k's later my mind took over and shut me down.

It was just bam! Nothing. I was hanging on and then it's like the lights just turned off. The tank was empty. I literally shuffled to the next feed station and folks took care of me. It took a good long while to recover. I mean, just eating a couple of granola bars, a banana and some water didn't make a difference. That race was over for me.

Had I stopped and grabbed a banana and Gatorade at the previous feed stations I actually may have been able to keep up with the lead group...for a while. Those guys just weren't human. There was no way I was going to hang with them until the end.

I bounced back a few hours later but it taught me a lesson, "don't ignore the warning signs". The warning signs for me, are some dizziness first, then tunnel vision and later loss of fine motor skills. I learned to never skip a feed station. I was fine until a few races later and I thought I could keep up with the big boys again. It didn't work out well.

First comes the fatigue, no energy to get up a hill, a really hard pull on the front where you struggle - struggle more than usual, maybe a dizzy spell but then you regain focus again. That's the warning. That's your body telling you to re-up...now. That point is different for everyone. World-class endurance athletes train to extend that time. They can mentally endure more than mere humans. But even they have their limits.


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PeteHski

Have a read of this:-

https://www.trainingpeaks.com/blog/i...210605_athlete

In summary, you don't need a keto diet to train your fat burning ability. You just need to do long, slow rides. For shorter, higher intensity rides you need the carbs if you want to be fast.

PeteHski

Bonking after a 10 mile ride doesn't seem normal to me. If had the symptoms you are describing I would be off to see the doc. Bonking is what happens when you run out of fuel, usually toward the end of some big endurance event when you haven't eaten enough carbs during the ride. Fatigue is more of a gradual loss of power and build up of soreness in your muscles with continual use. Unlike bonking, munching more carbs doesn't help with fatigue, only prolonged rest will reduce it.

terrymorse 

Not only long, moderate intensity rides increase fat oxidation capability. High intensity interval training (HIIT) also has been shown to produce improvements.

Changes in fat oxidation in response to various regimes of high intensity interval training (HIIT)

10 Wheels

Type Two Diabetic here.
I Bonk when my Blood Sugar Gets LOW.

Erzulis Boat 

As stated above, bonking is very different than fatigue and exhaustion.

Bonk is tunnel vision, legs locking up, passing out for a few seconds repeatedly while still on the bike etc. You are DONE. It takes a supreme effort to "make it home".

bOsscO

I've bonked a couple times, and when the tunnel vision kicks in I have to stop and eat/drink something.

freeranger

I've only bonked once, on the way back to my truck, while riding a rail trail. Luckily, I was only about a mile from it, and my wife had a little water left in her water bottle. I had failed to take enough fluids and/or food along (probably didn't eat enough before starting too). Physically could not pedal. Sat on the trail for a while, after drinking what little water my wife and left, and after a while, "hobbled" back to the truck. Got in and cranked the a/c and sat there for a while before driving. I've been tired from riding, where I didn't feel like continuing, but this was different. I physically was unable to continue until a slight recovery. To me, bonking means unable to continue, until you recover, whereas fatigue is where I could still go, it's just very difficult. Bonking once was more than enough!

Awesomeguy

how do you train your body to burn fat?

Awesomeguy

how do you train your body to burn fat?

Bearhawker

Stop eating carbs, it happens automatically. You'll likely notice some side effects that are often referred to as "keto flu" but are likely more properly thought of as carb detoxing. A body used to using carbs as fuel wants to stay in that state.

How long the transformation takes depends on a lot of factors. I'm not sure how long it took me: I started with a 3-day fast where I consumed nothing but non-caloric fluids and salt. Broke my fast without carbs and have been less than 20g/day for 3+ years

Even without any of the health benefits I personally enjoy, the fact that I'm never really hungry & can ride all day, day after day, fasted is worth it for me. I never realized how much of a slave to food I used to be until I made the switch. I eat when I want, not when my sugar runs out. Truly liberating.

PeteHski

Not saying it doesn't work for you, but really that's probably not great general advice. Or at best extremely contentious!

MoAlpha

By running out your glycogen and burning fat. It's not complicated. Anyone who goes out for a three hour ride and doesn't stop for donuts or slug Gatorade the whole time does it.

Awesomeguy

but what about bonking, since you are not eating but exercising so long?

MoAlpha

Lengthen your rides gradually and take along a bar or a couple of gels and a credit card in case you start to feel squidgy. There is no need to skip breakfast or starve yourself, although you certainly can and it may make the adaptation faster. Just make sure you outride your glycogen stores and don't stop for pizza.

GhostRider62

So true. When I am trained for it, I can ride virtually forever or at least 382 miles without eating and without bonking.