A blog by runners. For runners.

Why do I smell ammonia after a run?

Why do I smell ammonia after a run?I first noticed a strong ammonia-like smell in my nose after long, hard runs – more than 75 minutes – in warm conditions. Naturally, I asked my wife if she could smell it, too, but she couldn’t. It was all in my nose.

I decided to investigate.

Turns out, I was running too hard for my current fuel level and as result I was breaking down amino acids in my muscles to access more glycogen. When the body breaks down the amino acids to access glycogen one of the byproducts is … ammonia! Sometimes the body processes this in the kidneys and it is excreted in urine. Sometimes, when the kidneys are being worked hard or you are dehydrated, the ammonia is excreted in sweat. And sometimes that ammonia is excreted via respiration – yup, your nose.

So why did my body resort to amino acid breakdown for fuel?

When using your aerobic energy system, the body is burning fat – breaking it down for glycogen – and accessing glucose stored in the liver and in your muscles. When you carbo-load or adequately fuel your body with carbohydrates, this energy is waiting to be tapped. But stored glycogen has its limits. Long, intense runs can burn through your stored energy. And when that happens, the body goes looking for glycogen in your amino acids.

Fueling during your run with gels, energy drinks, or easily digestible foods can help, but the amount of carbohydrates you can pull directly from your bloodstream won’t completely help if you have inadequately fueled your body in the day or days previous to your run.

This means if you’re smelling ammonia you should pay more attention to how much and what you eat in the days leading up to longer, harder training runs. Proper hydration, even on non-running days, is also important. And learning to master long, easy runs will also teach your aerobic system to operate as efficiently as possible.

And don’t forget to refuel properly after your run. The general rule from most experts is to take in a meal three parts simple carbohydrates and one part protein. This will help you replenish your lost glycogen and amino acids. My preference is a recovery smoothie that includes whey protein powder, kefir, chia seeds, orange juice, a banana, and whatever fresh or frozen fruit (usually berries) I have on hand.

Disclaimer: I am not a trained nutritionist nor am I certified in anything other than trying to run faster through trial and error. If you have any symptoms associated with running that are concerning, consult your doctor.

Written by Rob Haneisen.