Thread: Why'd I bonk?
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Old 09-22-19, 08:51 AM
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Why'd I bonk?

Hey folks,

I bit off more than I could chew yesterday trying to up my endurance for long rides, and I'd love anybody's two cents on what the hell happened and why. The ride was 71 miles with 5700 ft of gain, climbing Old La Honda up over to the mighty blue Pacific, and then Tunitas Creek Road to get up back over to the bay. Epic stuff in my book. I had previously done the bulk of the hard part of this ride (the middle 40 miles with 4300 ft gain) twice on previous recent weekends, and felt good enough after the second time to give this a go. And hey, I made it. Nice.

Unfortunately, it wasn't all ...the nicest. I found out what bonking is all about when I was maybe half way up Tunitas. I had to stop maybe five times and just hydrate, eat some bar and stare at the ground like a zombie for several minutes. I felt like I had zero energy to push my legs forward. I was maybe vaguely nauseous, but basically just spent. I rode the whole rest of the hill VERY slowly, in stages with breaks, and feeling pretty damn demoralized. Shout out to all the friendly riders who asked to make sure I was okay as they cruised on by. And I'm glad to say that I was able to rally and ride at least functionally for the final 20 miles home from the top.

Thing is, replaying it all in my head, I'm still unclear what happened. Here's the facts of the case:
  • I didn't carboload for multiple days or anything, but I did intentionally eat some extra carbs the previous day. Consciously hydrated more than usual that evening too.
  • I ate three packets of oatmeal and a banana for breakfast, maybe like half an hour before heading out. Also sipped plenty of water while I was getting things ready.
  • I filled two 22 oz bottles and popped one and a half nuun tablets in each. Then I refilled these (and added more nuun tabs) just before the Tunitas climb (gotta love that bike hut.) So all together, at the time of The Incident about 3:15 into my ride, I'd polished off more than two liters of water, all of which had electrolytes mixed in. This felt like plenty for the intensity of my riding and the weather conditions, and if anything probably more hydrating than normal for me. I am definitely a heavier sweater than your average rider.
  • Over the course of those threeish hours, I ate two SIS gels (maybe 180 cal) and 1.5 clif bars (maybe 350 cal,) ballpark total 530 calories. Given the significant breakfast and the fact that I'd only been out there for three hours, I definitely felt like I was consuming enough fuel.
  • It heated up to be a hot day, but much of my ride was upper 60s/low 70s and shaded. There was one stretch on the coast with an exposed 400ft, 10-ish minute climb, but that was really the only time I felt like I was getting any intense heat on me.
  • I'm 6ft, maybe 195, been on a road bike (trek domane) for about 2 years.

So yeah. I don't think I clearly underfueled or underhydrated. I will say that I suspect it was a hydration issue somehow anyway, because on the long ride home I had some significant cramping in my thighs and noticed I really wasn't sweating as much as normal.

Any thoughts? Am I just off on my conception of what's necessary in terms of hydration and/or fuel for this kind of ride? Or just a wuss?
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