So this **** work, and it works extremly well. Almost too well. The only issue I have with it is hydration. If you are not well hydrated this will make you feel like crap. You'll feel very lethargic and bleh. But if you can drag your ass to do some cardio, holy **** is it amazing. Exercising at a sub maximal intensity I noticed 2 things immediately, I could breath deeper and slower, and my heart, not my lungs, was the limiting factor with my cardio. Typically when I do cardio after not doing it for some time, I'll expedites a burning in my chest, an odd taste in my mouth following exercise and I'll fatigue very quickly. But after taking this, the only thing that burned were my legs. My chest felt open and clear, and my heart became the only thing keeping me from pushing myself harder.