This question already has an answer here:
After exercising vigorously one can sometimes smell ammonia and it feels like it's coming from within the nose actually. There is no indication that others can smell it when I do (i.e. seems to be internal rather than external). I know I'm not the only one experiencing this, but I was wondering what the physiological processes are that are responsible for that?
Also: is this merely a perceived smell or is there actually ammonia in/on my body after the exercise.