Metabolic Acidosis (aka Bonking) on the Colorado Trail and Elsewhere

Mountain biking in Colorado
Mountain biking in the Tarryall Mountains

Ryan had never bonked before, at least in the metabolic shock/ overexertion sense of the word. When he started bumbling around and losing more and more of his edge, I knew that something was up and figured that’s what had happened. Not realizing what was going on, he kept on trying to mountain bike further up the Colorado Trail, although with diminishing returns. The big patches of snow that remained on the trail, even though it was June, were probably a good thing since they ultimately stopped and prevented us from riding any further. His disrupted mental and physical state likely made the retreat more palatable to the 13-year-old, since he wasn’t one to be prone to turn around before his goal was reached.

I’m sure there’s some sort of scientific or medical description for just what bonking is, although I never really studied it from a medical standpoint. But, I had experienced it first-hand more than once by the time Ryan was trying to figure out why his heart was beating so fast, and his legs felt like Jell-O. And so I had my suspicions that it might be just that.

The symptoms—weakness, fast heart rate, and disorientation are a bit scary. Thankfully, bonking often rectifies itself eventually, assuming that whatever physical activity caused it in the first place is curtailed. And, it is ultimately less troubling than some other maladies with similar symptoms. But to rush to the bonking conclusion too quickly (and perhaps wrongly) can be dangerous and not something I ever wanted to do. Seeing someone unable to do the physical tasks they usually had no problem accomplishing is disconcerting. But since I’d been in that state myself, as I observed his actions, I was able to predict what he was going to do next.

By the time he reached full bonk, we were several miles from the trailhead, which was not ideal. But since it was downhill almost all the way back to the van, the stretch of trail we were on was not physically demanding. And because I was carrying a lot of extra food (eating is part of the treatment for bonking), I was optimistic about the situation. Besides, there weren’t many other options, other than going back to the start, which we were doing, anyway.

Soon after we turned around, I stopped the group for a bit, and we had a rest and some snacks. I got Ryan to eat the rest of the food he was carrying and had noted that up to that point, he’d already consumed more than a quart of water. Good thing, I concluded, at least he’d stayed well hydrated and still had sufficient water for the rest of the ride.

Ultimately, we made it back to the trailhead. Ryan ate a bunch more food and was fully recovered within hours. He’d been introduced to one of the pitfalls of not fueling up enough during significant physical exertion at altitude and likely learned the lesson well.

On the other hand, I had the same thing take place three times through the years and was apparently slower at learning the same lesson. The first time it occurred was mostly because of my ignorance regarding what could happen to a body without proper fuel intake. I’m not sure what my thinking was leading up to the second event, but for whatever reason, it just happened. And that takes us to the third time.

Several years after the Ryan event and even several more after my first two, it happened to me again. As the symptoms began to develop, I brushed them off as a manifestation of weakness or lack of physical training. It occurred during a long mountain bike group ride in the Colorado mountains, which I’d actually done several times previously. I was careful to snack along the way and had a definite idea regarding the route and how it would likely all play out.

The length of the ride was 5 or 6 hours. While I typically didn’t tend to drink a lot of water while out riding, I initially did in this particular case. And by doing so, I stayed well hydrated, at least for a time. Even though the ride was long, I hadn’t carried a lot of extra water with me since I was aware we would be riding through a Forest Service campground about two-thirds of the way along the route where I could refill.

The group was composed of strong riders, and the pace was consistently fast. By keeping myself well-fueled and hydrated, I’d felt strong and had ridden in the middle of the group throughout the first portion of the ride. About midway through, however, and as we began riding the final stretch to the campground, I polished off the last of my water. As I drank the last drop, I confidently began anticipating the long drink that I would take at the campground hand pump while I refilled my bottle. I’d gotten water out of the pump several times during the previous summer and was pleased with myself for coming up with a plan to reduce the weight I was carrying by limiting myself to one bottle.

I felt strong and was in high spirits as we rode into the Lost Park Campground until I looked at the concrete slab where the hand pump usually was and saw that it’d been removed for the winter. I was speechless as I tried to think of somewhere else way out there in the middle of nowhere that had drinking water. I soon realized there were no immediate options other than the untreated creek water trickling along nearby. So, I decided I would just go the rest of the way without water and be thirsty.

We didn’t even bother to stop at the empty pump foundation as we rode on toward the saddle between Topaz Mountain and North Tarryall Peak. I felt sad and kind of sickened as we passed the place where the water had once been, but within only minutes, became focused on the climb at hand.

I soon began to feel the effects of the lack of water but ignored what my body was telling me. About 15 minutes after passing the campground, the climb to the pass started. I downshifted into successively easier gear combinations as the uphill progressed. As the pedaling became more difficult, my first thought was that I was just in too big or “hard” of gear and needed to shift into an easier one.

Eventually, I shifted down into my easiest gear combination and, at that point, was barely moving forward. I struggled to stay upright given my slow forward movement, although I was riding along at normal cruising speed in my mind. I finally realized how slow I was actually moving when the people behind me began to breeze past, seemingly without effort.

Suddenly, it became difficult for me to push the pedals for more than a few seconds at a stretch. My mind told me that it wasn’t all that steep, but my high heart rate and leg weakness each said something else. Within minutes I was bringing up the rear and falling further behind all of the time.

By this point, still almost a half-mile below the top of the pass, I realized I’d bonked. Had there been any water in a creek or a rut on the ground, I would have gladly drunk it. But there wasn’t, and so that wasn’t even an option. While that fact didn’t help my bonk situation, it more than likely saved me from other, potentially compounding intestinal ones.

Up to this point, I’d just been one of the riders in the group. But suddenly, a sort of “group dynamic” pressure developed in my own mind. I began struggling just to ride and became aware that the others were ahead and would likely be waiting for me to catch up. What was usually a leisurely fifteen-minute ride from where I was to the top became an inconceivable idea.

But I continued riding, even though I was only moving a few feet forward every minute or so. Because of the ridiculously slow pace, my greatest struggle was in keeping myself upright. Walking and pushing my bike would be faster, I realized. But my mind-fog prevented me from doing that and I decided that walking my bike would be an ultimate humiliation. Of course, I didn’t consider how pitiful I looked as I wobbled/rode along at less than a mile an hour.

After what seemed like hours of climbing, the trail emptied me into an open and previously logged area. I blurrily saw the group waiting for me at the far end of a clearing. They were barely a hundred yards ahead, and I attempted to look normal as I rode the last bit toward them. In reality, there was no doubt that things were not going all that well for me in anyone’s mind.

Eventually, I did reach them. The thing that riders sometimes do in such a situation is to declare that you were behind because you had “a mechanical.” But that was way too complicated for me to figure out in my feeble state of mind, and so just declared I was feeling a bit off, but was getting better. There were various food and water offers, but I turned them all down, saying, and lying, that I had plenty.

At that point, I knew the top of the pass was not much further. I reasoned that once I got up to that point, it would be smooth sailing from there back to my Tarryall mountain Base Camp since it was mostly downhill. But first, I had to get to the top. The ride from there on up to the top was not as pleasant as I outwardly tried to make it appear, but thankfullty, the pain was over within a few minutes, we crested the pass, and the downhill began.

It was a fast and painless descent for the others, but a slow and deliberate one for me as I rode at the back. While my speed (or lack of it) made the riding part physically doable, it also took me out of the route finding aspect. Typically, that wouldn’t have been a problem, except that in this case, the trail we were following was somewhat vague, and I was the only one in the group who had any clue about where it actually went. In addition to my bike riding worries, I was also suddenly the route finder.

My friend Tom was riding at the front. As we neared the bottom, I helplessly watched as he made a wrong turn. Immediately, I sped up and began yelling for everyone to stop. They all did, except for him, since he was too far gone. Realizing I needed to catch him, an adrenaline rush thankfully sped me up. Somehow, I passed the stopped riders without crashing and yelled at them to proceed straight across the creek rather than following Tom and then work their way on back to the camp. I also let them know that I would go get Tom and we’d ride on down to the main road. Then, once they got back to the camp, one of them should drive down the road and pick us up. And so, they rode off in one direction as I continued in another.

I continued on and finally did catch up to Tom, who was waiting at a creek crossing. I quickly gave him an abridged explanation of what had happened. Then, the two of us went on across the creek and began riding down a two-track that we assumed would painlessly take us on to the main road. Our plan was to get to the road and just wait for the others to pick us up and shuttle us back to the camp. It seemed simple enough, assuming the road did what we thought it would do. But alas, it didn’t.

Riding the two-track road was pleasant, for a time, as it continued descending toward the paved county road, that was visible some three miles off in the distance. I was thankful for the smooth and easy riding as we quickly covered two or so of those miles. All was good, and I was confident in my ability to continue coasting and rolling downward– until we came to a surprise uphill.

I was a bit disheartened to see and feel the road do what it did. But I assumed the uphill would be short, and so “attacked” the climb. My legs felt strong for the first couple of seconds of the ascent. But then, the next five minutes it took to ride the whole 100 feet to the high point were downright painful as my muscle-memory quickly remembered what’d been going on with my body less than an hour before. I would’ve cried, but I didn’t have enough fluid in my tear ducts to do so.

After a while, we did get to the summit of what I hoped was the final hill. We stopped, took a break, and thankfully saw the main road nearby and downhill. By this time, reaching the Tarryall Road had become my sole mission in life. All I wanted to do was get down to it and was cponfident that at that point, one of the others would actually show up to drive me back.

We finally did make it down to the pavement, and after only a short wait, one of the others showed up in his car to take us back to the lodge. There wasn’t space for my bike, so I just stuck it behind a bush and crawled into the passenger seat. I planned to return and retrieve it later that day, although, at the time, I didn’t even care about whether or not it was safe where I left it.

Once back at the camp lodge and after drinking three bottles of water, I began to regain my senses. When I returned to a state of coherence, I began to wonder about how the others had ever found their way back to the lodge and started worrying about my bike. After an hour of small talk and good-byes, everyone left, and I drove off in my pickup to get the bike.

When I got to where I’d left it, I was thankful to see it was still there. So, in the end, I didn’t lose much during the ordeal other than several pounds of water weight. And, as a bonus, I once again learned the bonking lesson. But it was then that I finally embraced the importance of staying well fueled and hydrated. I also definitively came to understand the pitfalls of assumption. And once and for all, I recognized the benefits of being well prepared.

Vail Race 012
Riding Downhill

Author: David Appleton

I was born and raised in Texas and currently live in the Texas Hill Country, spent some 30 years living in the smack dab middle of Colorado, and have spent a lifetime adventuring and leading others on adventures in many parts of the wild world.

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