About four days ago, while at the gym, I started noticing something odd. About two minutes into my cardio workout, just about the time I got my heartrate in zone, every time I exhaled, I noticed the faint faint odor of ammonia. I thought "weird", figured maybe someone was mopping one of the locker rooms, and dismissed it.
It happened again the next day, then yesterday, and now again today.
I can smell it only when I exhale.
This is beyond weird.
So, is ammonia a human metabolic byproduct? If so, is it normal to be generating so much of it while exercising?