How can you tell the difference between dehydration, bonking due to lack of food, and just not being fit enough? Sometimes on my long rides I get pretty miserable near the end and I’m not sure what I’m doing wrong. Are there symptoms that are specific to each possible problem? How do I know if I just need to ride more or pack more food or water?
I’ve never bonked and I try not to race past my level of fitness but I knew I was dehydrated at IMFL when I blacked out as I ran towards the finish and felt like I was drunk then woke up in the medical tent. The nurse asked me when was the last time I peed, and I said ‘uh…I didn’t pee at all.’ woopsie.
I then woke up the next morning with a hangover. I think I ran past Heavy D in the last 3 miles or so, but that’s all I really remember.
Bonking: I get dizzy, shaky, uncoordinated, mentally lethargic, body feels like it is searching for energy that it can’t find.
Dehydration: Feel weaker than normal. HR and respiratory rate are higher than normal for a given effort. Usually the cause of an off day for me.
Lack of fitness: Muscular fatigue, overall fatigue.
How long are your long rides? How much are you drinking? What’s the temperature? How much are you eating? How long have you been training and doing long rides? My guess is it’s a lack of aerobic fitness - it takes a long time to work up to and be able to comfortably ride 5+ hours without suffering at the end.
If you were bonking you’d definitely know it. Becoming dehydrated is easy to notice if you look at the color of your urine.
bump for monday morning people
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Could be lots of conditional answers here, but here’s my suggestion as I just went through this.
Start by recording your pre-workout weight to post-workout weight. If you have significant weigh loss, you need to address that issue with better hydration before you can look at the fitness or food issues.
In my case, I was losing massive weight in races and fixed with better hydration, Guess what, the perceived fitness and food issues were no longer there once the hydration issue was fixed.
bonking = head SPINNS, quick loss of all power in my body, almost a numb type feeling, can feel really miserable on the bike, like everytime I do a flip turn my head will spin off in the pool and like a loss of body control on the run - I used to bonk fairly often, but have not in a long time - I’m not the greatest with my nutrition (per training or during training) - to some degree I think I have taught my body to not bonk
I have never really dehydrated - very odd as I sweat a ton
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Unless you’re completely new to cycling, you are always fit enough to do a long ride. The question (and your answer) is “how hard.” If you’re getting tired and falling apart, it merely means you took it out too hard. You are fit enough to ride a long time;you just need to learn some pacing skills. The first hour or so of any long ride should be downright lackadasical. Boring, almost. Tired legs and general fatigue is a symptom of going out too hard, or riding too long at a given effort. Back off the pace just a teensy bit.
Bonking is another thing entirely and, unless you are taking in no calories, is unlikely. A couple hundred calories an hour – basically sports drink – is enough to carry you through. A real bonk is characterized by confusion, loss of balance, slurred speech. You literally have to stop and lie down. It’s a nasty thing to go through, and a great many people confuse plain old fatigue with bonking.
Dehydration – do you drink at least one tall bike bottle an hour? Dehydration will bring on many of the same feelings as general fatigue. A key difference: All else equal, fatigue means a declining HR that is difficult to hold up. Dehydration usually means a rising HR that is hard to get down. That’s the key signal for most people.
As other have stated about dehydration and bonking.
A couple add in’s.
Dehydration is often accompanied by naseau. If you sit down, lay down and the naseua goes away, you’re likely dehydrated.
Bonking for me is like a switch. I go from “I’m fine” to “Uhhh what happened to my legs?” This is usually accompained by a feeling of…“Wow what a nice day!..did you see the pink elepahant?” I’ve only had it happen once or twice but in both cases I didn’t feel like I was pushing it, but simply couldn’t push it any harder. Kinda like I was spinning and that’s simply all I could do…and darn it that’s ok…because we have pinks elephants along for the ride. Unlike fatigue where I feel like I’m pushing REALLY hard and just not going anywhere, the entire time being painfully aware that I SUCK!
~Matt
Thanks, your reply was really helpful. the problem usually comes up in the last 5 miles of a certain tough and hilly ride that is around 60 mi. I’ve gone longer without problems, but this one ride is different for some reason. I thought it might be dehydration because i generally only take two bottles with me and don’t refill anywhere. i also thought bonking because i only take around 450 cals for the whole 3 hrs. But my symptoms seem to more closely match fatigue. I feel like i can’t put any power to my pedals, not even enough to keep my heart rate in my ususal range (140-150) instead of dropping down to the 110’s. I guess I’ll try pacing myself a little more next time. thanks