“Daddy, You Smell Like …Pee”

Posted by Filed Under: Nutrition, Science and Research

That’s what my son said to me upon returning from my long run on Monday. Want to know something? He was right!

I’m sure I didn’t smell exactly like urine but, as you may or may not know, there is ammonia in urine and ammonia is the stuff responsible for the strongest odour we can smell in that particular liquid.

But why did I smell like pee after my run?

The answer is that there was ammonia in my sweat. This is explained nicely at Devine Sports:

Your body produces ammonia everytime you run hard. Whether you smell it or not is a different story, but your body produces it on every long, hard run.

The reason this happens is ammonia is a by-product of protein metabolism. When you run hard and long, your body burns protein and carbohydrates for fuel. When the carbs are burned off (or when there aren’t adequate carbohydrates), the distinctive ammonia smell presents itself.

The fact that ammonia is produced on every run doesn’t mean the smell is noticeable afterward. Usually the smell is only present when there is the carb deficit. This increases the ammonia levels in your muscles and the ammonia is then picked up by your blood and carried to your respiratory system. When this occurs, you can usually smell it. In addition, some of the ammonia will show up in your sweat which makes the odor even more noticeable.

The smell usually isn’t anything to worry about. But if it persists, you probably aren’t taking in enough carbohydrates. If you emphasize carbohydrates before, during and after running and the ammonia smell is still around, you should get checked out by a physician.

This isn’t dangerous at all. But it is a not-so-subtle warning from your body that it needs more carbs (rather than more protein) to burn on long and hard training runs.

The solution is easy: Eat more carbohydrates to fuel your muscles. Especially if you’re running longer than an hour or two your muscles crave carbohydrates which burn easier than protein. You can also do this by taking in in carbohydrates while running.

Simply drink a cold sportsdrink (which has carbohydrates) every 15-20 minutes while running. If your carbohydrate intake is adequate to fuel your running, the ammonia smell should disappear. Your body will still be producing ammonia, but you probably won’t be able to smell it.

So it looks like I need to eat more veggies.

Now if only someone could help me figure out why I sometimes smell like a pine-scented car freshener.

About Mark Iocchelli

Also known as the "Running Blogfather", I'm a 40-something marathoner who has beaten stress fractures and terrible shin splints. Now I'm running double the mileage with no pain - and I'm getting faster. I love to talk about running form and Arthur Lydiard. I also enjoy taking photographs, have a beautiful (and very patient!) wife, and am the proud father of two crazy kids. Feel free to contact me if you have any questions or comments about the site.

  1. Perry on November 10th at 12:26 pm

    It could be because of the bacteria living in your shirt. See this post I did on the subject recently.

    Of course, my smell could be because of the ammonia. Thanks for the tip!

  2. Soozan on November 10th at 1:28 pm

    Are you on a low carb diet?

  3. Mark Iocchelli on November 10th at 1:41 pm

    Perry: Nope. It was me, not the shirt.

    Soozan: Nope. I follow a balanced diet. This is just an indication I may have been low on carbs that particular day.

  4. Aaron Engelsrud on November 12th at 3:17 pm

    Yeah… Right… Just from the running…

    Mark, these types of problems are a normal part of growing older. 🙂


  5. Earthmovers and Sandcastles » Beaten on July 5th at 12:45 pm

    […] Eric what it meant that I came back in today smelling like ammonia. (Then, of course, I went and looked it up some more. Compulsive research, anyone?) I’d never say that I’m low on carbs, as a rule, but […]

  6. victor on September 7th at 12:58 pm

    This was very helpful, i was constanly thinking that my roomate was cleaning while i left and was starting to think she was a little batty 🙂 is this a bad thing i smell like ammonia strongly after almost every run. i like my diet and i feel good before during and especially after i run?

  7. SF SW on November 21st at 2:16 pm

    Wow, a pine scented car freshener? Lucky!