Are there any "good" gases which "accidentally" diffuse into the lungs and get exhaled?

Question

The purpose of breathing is to bring oxygen into the body and to rid the body of waste gases such as carbon dioxide and excess water vapor. This is done by diffusion with the blood. I am wondering whether the respiratory system also "accidentally" removes good gases from the body via diffusion and exhalation. (These good gases do not include oxygen, since it doesn't diffuse from the blood into the lungs.) This might be useful if a person has low amounts of a good gas and breathing too much, such as doing too much exercise, is the culprit.

Such good gases could come from food. Just like alcohol vapor is exhaled, maybe these gases might be exhaled too. Good gases could also come from a specific metabolic process.

Answer 1

Biological scientists do not usually ascribe moral attributes to metabolites, despite the use of the term ‘good’ in reference to lipids by those who communicate with the public. So I think it better to rephrase the question more precisely, as something like:

“Are there any important gaseous metabolites or signalling molecules in humans?”

One gas that comes to mind is nitric oxide, which is a natural signalling molecule that causes vasodilation of smooth muscle. The production of this is stimulated by the erectile-disfunction drug, sildenafil (marketed under the trade name, viagra).

Thus, nitric oxide fits the bill (and, in so far as a penile erection is considered a ”good thing” — most men will be of that opinion, nitric oxide can even be considered a ”good gas”).

Nitric oxide has certainly been detected in the exhaled breath of normal individuals, but the majority is excreted in the urine as nitrite or nitrate. So I would look for causes other than heavy breathing to explain the decline in its tissue concentration, and any unwelcome effects that this might have for the individual.