Hey all,

I think I bonked on my most recent 82-mile training ride. Throughout the first 65 miles, I ate four 140-Calorie granola bars and an enormous blueberry muffin, and drank two bottles of Gatorade and two bottles of water. I had a big breakfast immediately before the ride, consisting of a huge bowl of cereal and a big glass of juice.

The first 70 miles or so, involving maybe 3,000 feet of climbing, went along without much incident. At mile 70, I just started to feel lethargic -- not light-headed or sick, just totally beat. I still had a hill to climb and a certain Golden Gate Bridge to cross, but I just kept getting slower and slower. At first I just thought I was tired, that my legs were giving out, but that I was more or less okay.

Once I got on the ramp up to the bridge, I realized that it just had to be related to blood sugar. I plodded over the bridge at no more than 6 mph (I crossed it the other way at 17+), and became very preoccupied and paranoid about the people passing me. I felt like I couldn't react quickly enough, like I was out of control of where my bike was going. (And trust me, those crosswinds suck when you're barely moving at all.) I got across the bridge somehow, and promptly got lost returning to my car. (There are only two turns, and I had been there several times before.) I tried to read street signs, and literally decided it was too much effort to try to piece together what they were saying. I was beginning to tremble slightly, and almost busted my ass just trying to clip into my pedal after crossing a busy intersection. I became more and more lost as I continued to ride, going about two miles out of my way into bustling city traffic. I felt like I could have fallen fast asleep in an instant while standing at the stop lights. My mind was so sluggish that I actually crossed an intersection without really knowing if I had the right-of-way, because I just couldn't figure out which light was mine. My heart rate stayed north of 160 bpm, even though I was hardly moving.

Somehow, I found my way back to my car, found my way to a gas station, and bought some food. Oddly enough, I didn't have the ravenous hunger that was typical of an earlier 'near bonk' experience. In fact, I wasn't even hungry (or thirsty) at all. I almost had to force myself to eat. Also, unlike previous experience, I didn't feel better immediately after getting some glucose back in my blood. In fact, I didn't feel quite right in the head for several hours after the ride.

Was this a bonk? Or did I just over-exert myself? Is there any sure-fire way to tell when you're bonking, short of pulling out a glucose strip and a lancet? Could my malaise have been caused by something else? I'm going to see a primary-care physician tomorrow.

- Warren

1000 odd calories for 100km, is not enough.

That probably is a bonk, it's the same thing as over-exerting your self. You could have been over heated but I vote for bonk, too tired, whatever you want to call it. It sounds like a pretty normal bonk to me. It’s what happens to me if I bonk, but I have learned what to do now.
The trick is to learn to STOP riding when you start to feel that way.

Always have some calories available on the bike. For a bonk liquid calories get into you faster. When you start to get that tired STOP and get off the bike in the shade. Have something to eat and drink and be still. You may recover. I always recover with fruit punch available at the small convenience stores, it's fast and I like it. Gatorade, whatever, just get some calories in you and get out of the heat. With the right stuff you can recover and get going again if you are not too far gone. When you just begin to feel that way STOP. I get on the edge of bonk once in a while and I recover very fast with some liquid calories and stopping. The sooner you STOP the better. Solid food takes a lot longer to give you any energy.

STOP before you fall into traffic.

It was 100 miles, not 100 km. I didn't feel the onset of any symptoms until the 70th mile.

It was not hot -- in fact, it was cold. The winds around the Golden Gate make it a perpetually brisk environment.

I ate all the food I had on the bike in the first 65 miles. At first, I couldn't bring myself to ask someone else for food. Later, I was on the bridge's 5-foot bike path and there was no way I was stopping on it.

My main concern is this: how can I tell the difference between normal, expected fatigue and an impending bonk? I wasn't having neurological symptoms until I got on the bridge and couldn't stop. When I first started feeling bad, it just felt like I was baked. I thought "Wow, I'm going slowly, but man, my legs are just so tired. No big deal. Let the others pass you."

- Warren

Most deffinitely sounds like a bonk mixed in with some liver stress. Toxins from our modern, poluted lives are stored in our body fat due to most of them being fat soluable and will mostly sit there out of harms way. That's how our bodies work. Heavy exercise will induce our bodies to burn this fat and this is most likely what we want to do anyway however our poor liver has to deal with it and on top of everything else its not much fun.

Regards, Anthony

Toxins stored in my fat, eh? *rolls eyes*

- Warren

Your first thought about low blood sugar was correct and that was time to do something. Your natural instinct was 100% correct. It sounds like your first sign is the thought of low blood sugar. Follow that lead. If you're like a lot of people you will now start to remember that feeling when it comes back.

What operator said is very important. I think 3000 would be more like it. Maybe more.

clue #1: not enough calories.

clue # 2: I get confused but I can still ride.

I would get the same feeling you had on a bridge too, but my legs still work. I would not have stopped on the bridge either. I could keep riding, but I would get lost in a strange area too, just like you did. Trouble clipping out. Balance is bad when stopped. All classic bonk signs. I have trouble talking when I'm really gone.

At the first sign of confusion or difficult thinking that's it for sure. Welcome to Bonkville.

Don't forget the extra expenditure of calories your body experiences when you cycle in cooler weather. Reads like a big ol' bonk to me.

Try some slower burning carbs the night before, perhaps. Brown rice is a good example.

Dude, you didn't just bonk you hit the freakin' wall. Yikes!

IANAD, but it seems to me that you clearly did not even get close to eating enough. As mentioned above it looks like you took on around 1000 calories which is little more than an hour's worth (for someone my size at least) of riding. Check out the recent favorite ride food thread and eat more next time!

When my GF and I take new people on their first long rides, the first sign of impending bonk seems to be that they bring up food in the conversation. They'll be riding along chatting, and then suddenly you get things like:

"I used to be a baker" followed by a loving discussion of bread.

or

"I had waffles for breakfast!"

It totally sounds like a bonk, and the best thing to do is be aware of what you need to eat before a long ride, and how long it will last you, and how much you need to bring with you and eat/drink while you ride. It takes practice, and it's better to bring a little more than you think you need and not use it than come up short and have to slog home with low blood sugar.

A big bowl of cereal isn't a huge breakfast if you're going to ride 100 miles even moderately hard. A lot of pro teams actually have certain minimum breakfasts (this much pasta, this much toast, N glasses of orange juice, etc) followed by eating whatever they feel like. You don't have to eat like them, but you can find a balance of enough food and not so much that you feel too full or get sick to your stomach.

That's the thing, though. I didn't feel hungry at all at any point in the ride, or even after the ride. I just started feeling like my legs were toast (no pun intended!), and then, after crossing the bridge, happily discovered I was suffering pretty severe neurological impairment.

I certainly didn't eat enough for this ride -- one of the many reasons I don't like unsupported century-length rides on road bikes. There were a few opportunities to buy food at coffee shops and what-not, but I don't like standing in line for half an hour, letting my legs cool down, just to get a muffin.

I suppose the sense of general fatigue might be the first sign of a bonk for me. When it starts to feel like every tenth of a mile is agony, stop and eat something, dammit, whether you think you're hungry or not. I was just curious if there was some clear way to distinguish normal exhaustion from an impending bonk, but there probably isn't, and I should probably eat something either way.

- Warren

Yeah. Actually there is a lot of stuff that gets stored in fat cells. That's one reason why certain drugs cause flashbacks...the residual drugs get stored in fat until a point where the body draws upon those fats cells and then BAM!

Remember that dude from the Ukraine who got poisoned during their elections by one of the guys in the opposition? He had been given massive doses of thalium I think it was...so much so that he got really sick and his whole face ended up like a pock-marked mess. Well they were talking about giving him liposuction to help remove fat where the residual thalium was being stored...

For years I had been fighting against hypertension (high blood pressure). My lifestyle didn't help. In the past 4 months, I have been riding. I was progressing nicely, when suddenly I started seriously bonking on my short (15 mile) lunchtime rides. My fellow newbies started passing me and dropping me. I also noticed a light headedness. My blood pressure was dropping. I quit the meds as an experiment (I DON'T recommend this w/o doctor supervision) and found that I was yet again able to drop some of my other fellow newbies.

I have since went to my doctor and have the blessing to continue without meds and monitor my BP.

When I bonk I normally count it as a good day.

One leads to the other, and the line may be fine. To paraphrase Justice Stewart, I know the difference when I experience it. Feeling tired is quite different than the disoriented malaise of bonking. The former is, for me, mostly a physical sensation, but the latter is physical and mental. In the early stages of bonking, I may still be aware enough to recognize that I'm losing my mental sharpness, that I'm not thinking clearly, or not really noticing the terrain or other conditions of the ride. But even when the bonk first starts to hit, I can still sense that something is wrong, though I may not quite understand it at the moment, in my disoriented state. Sometimes, a sense of being on "auto-pilot"--as if I'm not really seeing anything, even subconsciously--can be a clue that I'm beginning to bonk.

Sounds like a bonk to me. Not enough calories and carbs for the length of the ride you were doing. For a 100 mile ride, I always bring a ton of food on those longer rides.Gu-Gel works great in these situations!

relax

that was a certified bonk

-train more miles at below lactate threshold, for at least
3 hours, twice a week-...this'll train body to burn more fat.

also carry more calories
or hit a store and get more food in ya. easier to ride
on a full stomach at half speed than on no calories
at no speed.


you just got the bonk. brain doesn't operate on low blood sugar.
best bet is to pull over and take a nap on the grass if it happens again.

If you look down at your arm and start having thoughts of biting into it, that's the bonk.

You may think you've learned a valuable lesson and vow to never let it happen again, but it will happen again.

Early onset of Bonk appears as lightheadedness to me. Then my speed drops. Then I know that the rest of my day is a wash.

Your stomach will not tell you when you're going to bonk, so you can't rely on hunger. Usually mental symptoms appear before physical fatigue sets in b/c the brain requires glycogen to function but the muscles can use fat as fuel as well. Something like that. If you're having a bad day you'll feel it pretty much from the beginning, but if you're feeling good all day and then you suddenly notice you're feeling depressed or bored, stop and eat before you bonk.

The climbing you did on your ride also contributed to your bonk. On a hilly ride you're going to bonk much, much faster and harder than on a flat ride. Was the ride considerably more difficult in terms of hills/headwinds than what you're used to, and did you tend to climb somewhat fast, as compared to staying in the saddle and spinning at a low gear?

I eat granola less and less now on tough rides b/c it's too dry and too much chewing for not enough calories. When you feel the bonk go with power bars, gels, etc.

bonk, bonk... bonkitty, bonka, a bonk....

It's like saying, you'll never drink too much right after a hangover. You know at some point it will probably happen again. You won't mean for it to, ....it just will. hee hee

Thanks for all the advice so far, guys. I have an update. I saw the doctor this morning, who took an EKG and found something that he troubled him. He did an urgent referral to the cardiology department at the local hospital to have a stress echocardiogram done... tomorrow at 3:30 pm. I'll let you all know what happens.

- Warren

Wow. Now it's serious.

Big hint: If you are riding and you feel hungry, stop and eat SOMETHING.

On my last century I only ate about 700 calories while on the bike. I ate a big breakfast 2 hours before the ride. When I got home I tried to eat my post ride meal, but was too full.

Definitely the bonk Warren. You were riding harder than your body could matabolize the food you put into it. Over time your body will get better and you'll get better estimating the speed you can ride and stay within your own capacity.

82 miles is pretty good distance and that's the point where I always start wishing the ride was over.

I assume you really hated the climb from Sausalito up to the bridge. I don't like that even under perfect conditions. Some jackass taxi driver hit me on that climb one time. Luckily it just threw my arm forward as he hit my elbow at speed. I was really glad I had my hands on the tops and not holding on. Whenever I can, I prefer to ride through Fort Baker and up the steep climb to the base of the bridge now though I do the Bridgeway climb when necessary.

I hope everything is OK. Don't be too worried though. Athletes have a funny heart beat that non-cardiologist often mistake for problems.

Yeah, that much is clear.

The problem is that I didn't feel even slightly hungry, even while my body was shouting all the other classic signs of hypoglycemia. My doc agreed that I probably should have eaten more, but he didn't think that was the whole problem. The tachycardia I've experienced after weightlifting is, apparently, very unusual, and he thinks it's related. I'll go lift for 20-30 minutes, maybe 10-15 sets of different basic exercises, and I'll spend the next 30 minutes light-headed, with my heart racing, my hands cold and clammy, and sometimes my ears ringing. I don't think that's a good sign.

- Warren