Originally Posted by Iride01

I don't think EPO in itself is a thing for making one able to sustain fast speed. What does do that is oxygen. And EPO is what spurs the production of red blood cells . So more red blood cells means more O2 capacity. But remember you just gave a pint of blood. So when your body gets the volume back to normal the EPO goes down.

I just have thrown this out several times to see what comes of it. So far none have really bit.

Though I might wonder if one that regularly donates blood tends increase their normal volume of blood between donations.

This is all just my ponderings as a un-educated lay person. So I've probably got something askew or just plain wrong. Trust what MoAlpha says if he/she cares to add more about it.