angry willy wrote:
You dimwits make me crazy.
You can already breathe in more oxygen than your body has the ability to transport. It wouldn't make a measurable difference in your performance if you were breathing air with 25% more oxygen. The biggest limiting factor is transport of O2 by blood. What does EPO do? More red blood cells, to transport more O2.
This is true. You need to consider the Bohr effect. At lower blood temperature, you're going to have lesser dissociation of oxygen from hemoglobin at a specific partial pressure of O2 - which means it stays bound to Hb, and not taken up by the cells. A "leftward" shift (opposite of the rightward shift, which happens when temps increase), for those of you who are familiar with Bohr.
If the OP was talking about lower air temperature, that wouldn't have much of an impact on the blood temperature. Unless it's so cold the person is hypothermic. Then the person has more to worry about than running fast.