Andrew Huberman· PhD
You inhale air and that air and the oxygen molecules in that air actually move from your lungs into the bloodstream because these little alveoli of the lungs, those little sacs of air are in there, they basically have a lot of little micro vessels and capillaries, little tiny, basically blood vessels, essentially, although they're mostly capillaries, micro capillaries are the little tiny ones, that line them, so there's actually an interface and opportunity for air and molecules within the air to pass into the blood and then they move in your bloodstream, and when you exhale, the opposite is true.