To Dalai and others that commented on my "6 weeks" note above:
I was OK for everything *except* high-performance cycling within a day. When I rode my bike a week later, my peak heartrate was still 10-15 bpm higher than I could achieve prior to donating blood. On a regular hour-long climb that I ride (solo) every week, I didn't match my pre-donation times until 6 weeks had passed. This isn't comparing my output to other riders, it's a semi-objective test against a fixed goal.
It's not that I was impaired from normal daily life. My long recovery time might have included lost fitness, not just blood replacement. But it took a long time to get back to the performance I had prior to donating.
Thanks for the responses to my post. However as I was asking for personal experiences when you say you didn't reach your pre-donation time for 6 weeks on that particular one hour climb you pretty much answered my question. Your point that during your recovery time (the 6 weeks) you may have lost fitness due to the inability to possibly work as hard is a good one.
I know I push myself as hard as possible on my rides as I assume others do so I am looking for the ability to recover whatever peak I had before the donation.