Jed Clampett wrote:
If it isn't bad for you, then why does being active as in your last paragraph feel better, than if you lay down?
Acid is cleared from muscle by the blood. Blood supply depends on vasodilation, which is regulated partly by nitric oxide, which is released by red blood cells in response to shear stress from working muscle. Stop moving and blood flow slows.
This is a review of pretty much every study about hemoglobin and blood gases:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3824146/