Projo.com: Sean McAdam: In tragic times, Sox fail to step to plate

I promise this is my last Red Sox post till the end of the season (short of the most stunning comeback in MLB history).  I think calling the Sox “heartless bastards” might have been kinder than the tenor of this column.

Anyways, my main question here is the intelligence of professional athletes giving blood.  I had always assumed that the reason you couldn’t give more than once every 6 weeks or so is because you have to regenerate the red blood cells taken in the donation.  This lower amount of cells would in turn causing easier fatigue etc. at least for a short time.  Is this true? And does it really cause any effect?  I’m not saying that Joe Schmoe in his local slo-pitch league shouldn’t give blood (though I probably wouldn’t the day of a game), but should people who rely on their stamina for their livelihood give blood?  If it is suggested you lay off the alcohol for 24 hours after giving blood, should you run around on a football field chasing after Marshall Faulk after doing so?  If any doctors can let us know that would be great.