Sports medicine pearls and pitfalls: athletic performance after blood donation.

Introduction Recreational runners and cyclists ask me if donating blood will slow them down in their weekend racing. Sure, I tell them, but only for a week or two, and donating is worth it. Blood donors are community helpers. Not long ago, I was asked: If an NFL team sponsors a community blood drive, can players who donate a pint of blood on Tuesday play to their full ability in a game 5 days later? That one is harder to answer. First, some background.