Before I begin I want to add a small disclaimer. I do not claim to be an expert on this subject. I am not a doctor and have no medical background, nor am I a scientist or dietitian. This article is not making any claims or diagnoses and should be read for entertainment and discussion purposes only.
It seems to happen to more than just cyclist. From what I found it happens to runners and weight lifters too. More than likely it happens to most athletes that workout hard or long. I have never experienced this smell after weight training. I have been lifting for years now and I can’t remember ever smelling the aroma of ammonia. Now, I have noticed the aroma during running workouts or races but never thought that much about it. It really wasn’t until last year that I started to notice almost every time I got in the shower after a ride I could smell ammonia. Not always in the shower but most of the time the smell would be strongest when taking a shower.
As I’m putting my thoughts together it seems clear to me that when I notice the smell the most is when I ride routes by my house. When I get home I jump right into the shower because I am hot and sweaty! When I ride by my house I have to say that I push it all the way up to the point where I only have about ¼ mile or less for cooling off. So usually when I get done my heart rate is still pretty high. I will explain more of my thoughts on this later…
I have to say that I started to get a little concerned with this because of the frequency of the smell. I am a firm believer in listening to your body, it usually knows! Once I started being concerned with the odor I asked my wife if she could smell it. I would ask her to smell my face, hair, and I would even breathe in her face… (I know, that sounds kind of funny.) Anyways she could not smell it? I thought something has to be going on and it’s probably not good?
Interestingly enough what you smell is actually ammonia (NH3).[i] Ammonia is a byproduct “of stripping away of the nitrogen molecule from amino acids so the remaining carbon can be converted to glucose. The nitrogen then bonds with hydrogen to form ammonia, a component of urea,”[ii] which usually leaves the body through sweat, urination, defecation and if the concentration is high enough expelled through the breath. Another possible cause of this smell is a high concentration of acetones in the system. This is a result of the chemical reaction of the liver breaking down fat acids for energy. The breakdown of fatty acids creates three ketone bodies, two of which gets used for energy (acetoactic acid; betahydroxybutyric acid) and one (acetone) which is usually excreted from the body as described above.[iii] Acetone has the chemical make-up of a solvent (CH3)2CO, so as you breath this out you may have a “cleaner” smell as well.
Our bodies have a hierarchy of cycles it goes through when using energy. The first source it uses during exercise is carbohydrates that are in the form of glucose in the blood and glycogen found in the muscle and liver. As these stores are depleted the body will start to break down fat cell stores. As intensity increases the body will begin to break down amino acids for quicker energy. This energy source is found in the muscles. People tend to think that these energy sources are turned off and on like a light switch, either all or none and only one switch can be on at a time. Our bodies are amazing and one of the amazing things is the ability to regulate itself. It will use all three of these energy sources at the same time and more of one than the other depending on the need at the time.
While researching for this article I have been training according to Coach Rob’s plan. I had a power test this past weekend. The test was a total of 30 minute with a 30 minute warm up. So a total ride time of one hour. As I was in my last 20 or so minutes of the test I noticed “that smell,” when I checked my heart rate I was around 173-174 bpm, which is around my lactate threshold. This is the first time that I have noticed what my heart rate was during the smelling sensation. I was in my anaerobic exercise zone!
Now, I know that I have only been able to confirm this one time so far, but I’m going out on a limb and say… that the ammonia smell is affiliated with the anaerobic training zone. So it seems to me if we look at the training zones there we will find the correlations between training zones and the way our body derives its energy. Whether it’s using glycogen stores from the liver or breaking down fat cells for energy. This may not be news to some but for me it is more detailed knowledge about what I enjoy doing… exercising and staying healthy. And finally figuring out where is that smell coming from?
There is so much to say about this subject that I can’t go into it all. This is such an interesting subject that I will look into more deeply in the future. What I find useful is I now have a physical indicator that lets me know when I have hit my LT. Most trained athletes can maintain their LT for about 45 minutes. This can be of use to you especially during Time Trials… am I working hard enough? Obviously, when you are training, being aware of this can be of use as well.
Some other things that may be contributors to the “smell” are dehydration. If you are getting dehydrated the concentrations of either of these processes I have talked about can be perceived sooner and stronger. I have my bike computer set to alert me every ten minute to remind me to drink. Sometimes I forget to drink while riding so I have a little reminder all the time. I would rather drink before I get thirsty!
If you have insufficient carbohydrates in your system and you are training for an hour or more you may encounter the ammonia smell. That is one of the reasons I try to have some carbohydrates about every thirty minute or so when on long training rides lasting more than 1 hour, so as to not hit the wall. Once you hit the wall or “Bonk” you are usually done! (That’s another subject for another time) Or if you are on a starvation diet and losing a lot of weight in a short period of time your body is producing more ketone than normal and you may smell[iv] “the smell… “
So it seems to me that this ammonia smell is not a harmful experience its just letting you know that your body is working and probably pretty hard! Good for you, keep it up and just make sure you have good nutrition and hydration habits and you should be fine!
One side note I did find where smelling ammonia could be a sign of something serious, and that’s if you have type 1 diabetes. If you smell “ammonia” and you have type 1 diabetes see a doctor right away! I didn’t get too far into why but it has something to do with low liver glycogen stores and blood sugar levels. (Apparently not good for a type 1 diabetic)
Until next time,
You can check these other articles, blogs and book to learn more:
Protein Power copyright 1996, Michael R. Eades, M.D. and Mary Dan Eades, M.D.
[i] Why do I smell ammonia after I work out?, Yahoo answers, Source: http://answers.yahoo.com/question/index;_ylt=A0LEV1GuNfRSr2IAMSRXNyoA;_ylu=X3oDMTEzZTNidmRzBHNlYwNzcgRwb3MDMQRjb2xvA2JmMQR2dGlkA1ZJUDI4Nl8x?qid=20070123055216AAW8A3n
[ii] Acidic smell after cardio exercise, Michelle Matte, March 29, 2011 http://www.livestrong.com/article/290746-acidic-smell-after-cardio-exercise/