Effects of blood donation on exercise performance in competitive cyclists

This study evaluated 10 male cyclists before and after phlebotomy to determine the effect of donation of 1 U of blood on exercise performance. Each subject underwent maximal exercise testing with oxygen consumption measurement at baseline, 2 hours after phlebotomy, 2 days after phlebotomy, and 7 days after phlebotomy. Maximal performance was decreased for at least 1 week. Submaximal performance was unaffected by blood donation.