Might point precisely...you used the word naturally. If your body doesn't do that naturally and there isn't a medical reason to help it along, then the opposite term is un - natural.

A better way to open the pathways is to do low heart bpm cardio mixed in with some higher intervals which will help improve overall cardiovascular fitness - aka, opening those pathways. That's the natural way.

Fuck all that supplement stuff. I don't trust any of it. None of it is natural, so either you will get some nasty side effects, or your results will disappear after you stop taking it.