Yesterday I rode with a friend at work around Mercer Island and then rode home from Seattle, a total of about 65-70 miles. While I ate my usual breakfast and lunch, looking back I was definitely under fueled for the pace I was setting and the distance. Not to mention I only had one water bottle and it was empty about 40 miles from home. I ate a cliff bar on the way, then refilled my water bottle about 15 miles from home, but it was too late. By the time I hit the big hill on the north side of Orting going up to Bonney Lake I was smelling ammonia and my pace and cadence had dropped big-time.
I’ve only bonked once or twice and it’s a miserable enough experience that I always make certain that I’m fueled and hydrated on my long distance rides. Well, almost always.
So what’s up with the ammonia smell? Before researching it, I figured it was either due to dehydration and my sweat was causing the smell, or that it was my body burning muscle or protein because it had run out of carbohydrates and/or fat. I’ve included a quote found on a forum and a link that describes it in a bit more detail.
Catabolism yes, fat-burning, no. Burning ketones does not produce a characteristic ammonia smell, as ammonia is nitrogenous in nature. Nitrogenous byproducts of cellular metabolism tell you that you have begun to break down proteins (amino acid chains - amine=nitrogen group) for energy.
This can be due to a number of factors - primarily having too low of muscle glycogen levels, or not having enough carbohydrate included in your diet. Conditions like these can occur after intense efforts either above your normal training zones or longer in duration than usual. I have noticed that when body fat percentages get very low, this tends to happen more easily as well, but do not have scientific rationale behind that thought - just my own experiences.
To solve the issue, make sure that you are including sufficient carbohydrates in your diet. Especially important will be the complex carbohydrates found in whole grains and low-glycemic fruits. Eating such foods in the hours before an event or difficult training session are key to priming your metabolism for exercise. Also, don’t down a “power shake” containing copious amounts of protein before a ride, as your body will be more likely to begin to burn this protein for energy once glycogen levels become low enough. Leave protein (in roughly a 4:1 carbrotein ratio) for your post ride snack/meal - it will serve your body much better.
So, don’t go carb crazy and jam down 300 or 400 grams pre-ride, but I’d increase your levels a bit (such as an extra piece of whole wheat toast, or a grapefruit with your pre ride meal.)
Also, perhaps rest a little more between your harder days to ensure that your glycogen levels are being repleted fully (glycogenesis). Drink plenty of water to help aid in glycogen uptake into your muscle cells.
As a side note, to train your body to better metabolize fat on longer rides and/or higher intensities, look into “bonk-training” once or twice a month - it can work wonders for some people.
BodyBuilding.com Article on Ammonia Smell
Hey Vin, if you’re reading this, I’d be interested to hear what the Cyclist’s Training Bible has to say about this.