Truly elite endurance athletes use epogen or blood doping techniques to gain this edge of perfection. EPO is the primary drug used by long distance runners. It increases the oxygen in your blood. I have spoken with olympic trainers that explain how it is beneficial for a meet, but not for long term. By long term, I mean that the effects do not last long term and that you certainly don't want to use it long term.
Most serious endurance athletes train in an oxygen deplete atmosphere, thus increasing lung capacity over time. The lungs actually expand and can hold more air. When they compete in a normal oxygen rich environment, they don't get winded nearly as easily...they take in more air full of oxygen.
When training in low oxygen environments comes to an end, and the body goes back to normally oxygenated air, the lunges shrink some...they revert to their initial size (to a degree, not 100%...or so it would seem).