Jarrett2

I'm trying to learn a little more about what bonking is, what causes it and if once you have it, you are more susceptible to getting it again.

My brother (53) and I (42) have been riding and losing weight this year. A lot of weight. Between the two of us, we have lost well over 200 lbs and ridden 3000+ miles over the course of the last several months. About a month ago, my brother was doing a solo 40 mile ride and didn't factor in the wind on his return path. He went out 20 miles and turned around into a 20+ MPH wind and had to ride back into it. He had never faced that kind of wind before on a ride.

During that ride, it appears he bonked, not knowing what bonking was, but he just pushed through it. He had to stop a couple of times, once to get some food at a convenience store, but he continued to push back through the wind on the return 20 mile ride. After this ride, he felt terrible. The next day he and I went for a ride and he made it only 7 miles before he had to go home. And every time after that he felt weak when he would exert himself. Not too long after that he came down with a bad chest cold that put him out of commission for another couple of weeks.

So flash forward to yesterday, he was feeling good enough to try and go for a ride after a month off. So we went together and I made a point to keep it at a very moderate pace on a flat trail with little to no wind. We did 10 miles and he said he started feeling the weakness coming on again, so we went ahead and wrapped it up.

I'm wondering if all of this has to do with the original bonk. And if so, is this something he will be more susceptible to going forward? And if so, what should he do to keep it from happening? Thanks in advance.

jsigone

what are his eating habits before and during the ride?

10 Wheels

He needs to see a Doctor Soon.

He did not Bonk on that first report.

Bonking is when your brain runs out of Glucose in the blood. You cannot ride when that happens.

TrojanHorse

I agree with 10 wheels. Bonking is when you stop & feel so lightheaded & dizzy you can't continue. It's also not a chronic condition.

I will say that over exerting yourself can leave your body susceptible to getting a cold or some other routine malady, which may explain the chest cold.

genejockey 

My experience with bonking was that it was possible to keep going, but only just. My legs would just barely turn the pedals, and I felt stupid and unable to make decisions, and just overwhelmingly tired. It hit 2 miles from home and I really had no choice but to keep going (pre-cellphone era). When I got home, I wanted nothing so much as to just lie down and sleep, but a tiny spark in my head said, "EAT!" so I ate a cookie and within minutes was back to normal.

Conversely, if he was coming down with the chest cold but not feeling it yet, it might be the reason for the poor perfomance/weakness. I've had the experience of going out for a ride feeling okay, but my HR was elevated on the easy sections, and I also couldn't raise it to the same levels nor put out the kind of effort I usually did, and then a day later I came down with a cold. It's also reasonable to assume that if he WERE coming down with a cold, and exhausted himself riding, it could hit much harder.

Jarrett2

He went to the doc, ran a battery of tests. Nothing. Everything was good. EKG said resting heart rate was athlete levels. Not sure what he is eating before, during or after rides. I know he has been on low cal diet for better part of the year.

the engine

From the Ops description, it sounds to me like something else is going on ... not related to bonking.

The rule of thumb for "bonk" prevention; Eat before you are hungry, drink before you are thirsty.

No, "bonking" should not be a chronic episode, unless you don't follow the rule stated above.

As far as sickness, post ride, which lingers for a period of time. It likely has nothing to do with "bonking". I would be looking at something else ... cold, flu, or possibly fatigue do to some other stress on the body ... lack of sleep, over training, ect., which can run the body down over time.

I doubt "bonking" would be the culprit here.

genejockey 

The other thing that occurs to me is that a chest cold can really drag on and take a considerable time to resolve completely, and then still leave you with 'twitchy' lungs. I got a nasty case of bronchitis when I was about 30 - coughing like crazy, wheezing a bit - that took weeks before I felt really well again. For YEARS after that, my lungs were very susceptible to Exercise Induced Asthma, especially on cold days.

JReade

You hit the point where you can't move the pedals to maintain momentum, and fall over. In my foolish youth (a year ago), I was riding a lot more, but partying as well. I went out on a friday night, knowing I had a ride in the morning. I made the ride, but between the hangover, and the lack of nutrition, I pretty much stopped moving at mile 55 or a 65 mile ride. A passerby gave me a soda, and I fell asleep on the sidewalk, coke can in hand. Woke up about 15 minutes later, feeling better, but couldn't speak in complete sentences, and riding was a challenge. Only gas in the tank was the sugar from the soft drink. Texted a friend to come get me, I would have been on the road for another year to make that last 10 miles.

SethAZ 

I disagree that a person must literally collapse to have bonked. The body will shut the muscles down before that happens completely in order to keep the brain alive. When you suddenly feel that lack of energy and it's an act of complete willpower to just keep moving at all because your glycogen is depleted, you've bonked, even if you haven't passed out yet.

OP: read articles like this one to help you understand what bonking is.

The short version is that your body cannot break down fat fast enough to generate enough fuel during high-intensity exercise, so that eventually, if you don't slow down or eat some food that your body can get energy from quickly, you will deplete your glycogen, your glucose levels hit rock bottom, and to keep your brain alive, your body shuts down.

Articles I've read suggest that for many high-intensity athletes, they can store enough glycogen to last around 90 minutes without refueling.

As for my personal experience here, I learned about bonking after doing it several times while trying to ride hard and long while burning off bodyfat. I thought that long, hard rides were a good way to force my body into fat-burning mode. Well, it is to an extent, but if I push it so long and hard that I bonk, that really sucks, and is counterproductive.

In my experience, if I'm generally eating a very controlled calorie diet (ie: I'm in weight-loss mode) I can fairly easily sustain my 25-mile bike rides without any additional food. These rides take me between 1:15 and 1:30. Doing my 34-mile rides is getting close to the limit, ie: by the end of these rides I'm starting to approach that bonking feeling. Having experienced it, I can sense it coming on. I'll be noticeably run down. Anything past 34 miles I won't do without having some sort of energy source, even if it's just a water-bottle filled with extra-strong Gatorade (for the sugar, not necessarily the electrolytes).

For group rides, for instance, where I know we might be riding as far as 50 miles, and at a very fast pace, I won't go without at least a water bottle filled with strong gatorade (I buy the powdered mix and mix it twice as strong as usual for in-ride energy) and something to eat, like a handfull of granola, a small sandwich, an energy goo, some small chewy candies, or whatever. I'll start consuming these things a half hour into the ride, so that the body will have time to extract the energy from them and get it into my system and usable. The strong gatorade seems to become active the quickest, which makes sense if you think about it.

Anyhow, the lesson here is that you might be able to hike all day without eating, you might be able to walk for hours and hours without eating, but you probably can't ride a bike hard for that long without bonking. If you use a heart rate monitor, you can check your heart rate during the activities you can maintain for long periods without eating anything, and then compare it with your heart rate where you can't, and you'll see the types of ranges off effort we're talking about. In my case, really hard, ass-kicking hiking in hilly desert terrain near where I live, with a 40 lb pack on, will only take my heart rate into the 110s to maybe 120 if I'm really kicking butt, and 100s if it's all flat terrain. I can ride for a long time without food if I keep the speed down to where my heart rate is in the 110s or so. Get well into the 120s, and certainly by 130bpm and higher, and I will need to eat or drink something to boost my energy if I'm going to be doing it much longer than an hour and a half or so.

JerrySTL

I wonder if dehydration is part of the problem? I've even heard it said that there's two kinds of bonking: low blood sugar and dehydration. Some people keep themselves partially dehydrated all the time.

Still 10 miles shouldn't be enough to cause a bonk of either type unless the person is starting the ride in near starvation mode or severely dehydrated already.

bigfred 

Too many unknown variables for any of us to comment definatively.

I'm in the camp that doesn't believe you need to be close to collapse to label an episode a "bonk". Depending on the circumstances, simply running out of glycogen and no longer being able to maintain an otherwise reasonable pace after 120-180 minutes could be labelled a bonk in my book.

In your brothers case:
What sort of diet has he been on?
Has he modified the diet since the incident?
Does he consume appropriate pre-ride nutrition?
During the ride nutrition?
What sort of body weight and pace are we talking about?
What is his perspiration rate?
How much fluid does he consume pre, while and post ride?

There are a lot of questions that would need to be answered to really get to the root of his issue.

For what it's worth a really serious bonk/dehydration episode can take a year or more to recover from. But, it's highly unlikely that he would have experienced anything close to such an episode on a 40 mile ride.

It's more likely that he may not have been conditioned for the continual output necessary to ride into a constant head wind, already starting the ride in a depleted nutrition state depending on his diet and pre-ride consumption, may or may not have eaten and drank sufficient during the ride, exhausted his glycogen stores and fatigued his muscles to a point not previously experienced.

As a reference point, I consider 3 weeks to be my average recovery time before feeling whole again after a really serious effort (race, event, break through workout) of 60-100 miles. And that's with careful fueling, ample hydration, post ride replenishment and not having bonked.

brons2

I used to have "bonks" that related to drinking plain water on rides. I was eating enough food, but I would drink plain water and at some point during the ride, especially on warmer days, I would just start feeling nauseous and weak. Would have to pull over and felt like I was going to throw up. I think what I was experiencing was the onset of hyponatremia. I've been able to get past these issues by never drinking plain water on rides. Always something with electrolytes. On hot days, I will get a V8 at rest stops which has something like 1000mg of sodium. Keeps me going.

SethAZ 

Btw, this past April I was doing the Spring Classics challenge on Strava, and I was going out on bike rides two to three times a day. I was also hoping to lose weight, so I wasn't appropriately refueling after each ride. One day I went out to do a basic 25-mile ride at a pace that wasn't even all that hard, and I bonked at the 21 mile mark, and it seemed like a herculean task just to roll home those last 4 miles at like 8-10 mph.

That's really when I read a lot about the subject and learned what it was I'd experienced (and had experienced before). On that particular day, I was starting a ride with severely depleted glycogen stores from all the riding I'd done in the couple weeks prior without proper refueling. I ended up doing 985 miles that month, and it would have been more but I had to skip the last few days to travel for a funeral. The second half of the month, though, I was refueling after each ride by drinking a concoction of protein powder and hershey's syrup mixed with skim milk. Hey, it totally worked*.

*I don't do that normally, that was what I did that month when I was riding two or three times as much as usual, and needed something extra.

Pamestique 

I had a friend that constantly bonked... just about every ride... when feeling good he was very strong but then... so this was his habit; he didn't seem to get it was not good for him...

drink almost every night until passing out.... on the Friday before a Saturday ride, would party; out until 2 - 3 and get no rest; alot of alcholol in the system. Saturday morning get up 20 minutes before ride, quickly dress (without allowing the body to process properly) and grab a Vente of Coffee and a sweet roll on the way... first 30 minutes of the ride totally buzzed, hyperactive; could not keep up with him. Then the bonk came... I can't tell you how many times I would circle back and find him bent over at the curb looking gray.

If your brother's habits are similar, that's your explanation. Common sense is get to bed early before a ride, eat a good dinner and hydrate with water the night before and then get up early to have a good breakfast, some water and process bodily waste before going on the ride. During the ride should be hydrating and eating something on a regular basis. If your brother is doing all that and still bonking... something is wrong.

Also, is it about trying to keep up with you? Have you tried starting out nice and slow?
That happens to me - I have friends who are faster than me and I make the mistake of trying to pace their pace... my legs never warm up.

Is your brother on any medication - just as BP or Cholesterol - both affect performance.

genejockey 

In other words, "I'll sleep when I'm dead, which should be... Oh, any time now!"

Jarrett2

Thanks everyone for all of the good input. I'll take some of this back to him.

ChuckD6421 

One other thing no one's mentioned; headwinds are murder psychologically. Since the winds are pretty predictable where I live I try to plan my rides with a nice tailwind finish. But the way out can be a real deathmarch sometimes. Obviously we weren't there, don't know what he ate (gotta fuel regularly on anything over 90 minutes or so with carbs. No matter that you're trying to lose weight), but it could've been the perfect storm of all these things.

But don't underestimate the mood-dampening effects of headwinds.

copswithguns

If it hasn't been said, bonking can be caused by lack of hydration. A lot of people feel like they have nothing left in the tank, when in reality they need to drink more. It's happened to me.

bigfred 

I had been thinking about this thread as I approached my new reduced fatigue limit this morning. And was thinking about writing a post about significant muscle fatigue and how long that can impact and take to recover from.

But, I reread the original post and what really caught my eye was the fact that the OP and his brother have lost a collective 200lbs this year. That's HUGE loss! I can't imagine that either of you have achieved that without participating in realatively restrictive dieting.

Have the two of you been consulting with any sort of dietician?

He could be facing a combination of nutrition issues, muscular fatigue, etc. My recommendation would be that it's time to consult someone professional.

Jarrett2

No consultation other than talking to our doctor about it. He seems to be supportive. My brother is starting to feel like this is where his issue is stemming from, but we can't find any information supporting that. I'm not sure what his daily caloric intake and burn has been, but I think I remember he was running lower than I was on intake.

Both of us have been using the Lose It app and have been more aggressive than the app recommends. Since he started having problems, he stopped and started upping his intake and zero'ed his exercise. I have continued with mine and feel great. Mine is around 1800 intake a day and anywhere from 0-1500 calorie burn a day.

bigfred 

If both of you are reasonably heavy, with correspondingly high base caloric requirements and you're only consuming 1800 calories per day and he's consuming even less than that, I suspect nutrition is the primary contributor to his issue(s).

Time for you guys to find some professional nutritional advice in the greater Waxahachie Metroplex area.

Jarrett2

Are you doc by chance? Just curious what leads you to believe 1800 is low.

Pamestique 

I am not a doc... just someone who has used a nutritionist, dietician and been involved in several major weight loss programs (and yet am still fat!).

For most young men, engaging in average to moderate activity, 1800 is low. Generally 2200 is recommended. If you are in a medically supervised weight problem, where your electrolytes, metabolism and other levels are monitored frequently, then you can probably try going much lower but for males 1800 is fairly low. Woman may be able to get away with 1500. Foods need to be something that readily translates into fuel - for instance if the calories are mainly from complex carbs such as greens, with low sugar or sodium levels, you may not be generating enough fuel to ride. You have to be very careful, because there is not much to work with, with balancing slow acting carbs with fast acting carbs, proteins and fats.

Experiment... just before a ride have your brother take 2 or 3 Shock Blocs (electrolyte replacement) and see how he does. If he does better then maybe its just his balance of foods that need adjustment.

BTW it would be much better to up calories in and keep exercising than the alternative... just becasue someone loses weight, doesn't mean they are healthy... exercise helps with the healthy....

BaseGuy

Sounds like he (and you) just need to bring a bit of FOOD along. As a very general rule-of-thumb, it takes about 90 minutes to deplete the energy in your bloodstream.

You can read a lot on the topic and educate yourself very well, but here's my quick take on it:

1. If you plan to ride 90 minutes or longer, bring some food!
2. Stop no later than the 60 minute point to eat.

I like a large box of raisins (the box about the size of playing cards). Easy on the stomach, good carbs, small, no clean-up, does not require water to eat, easy to throw in a pocket or under-seat bag. A banana is good, too, but a bit harder to carry. (Gel packs work, too, of course.)

You can also mix some powedered sports drink into your water bottle. I like original Gator Aid, mixed about 1/2 strength. I get a few calories with each sip.

Y'all keep that riding up! 200 pounds, between two people, is huge. Nice work.