Blood donation before a big ride?

[Pedal Wench]

The woman I spoke with assured me that I should be fine provided I drink plenty of fluids before the donation and afterwards, and that it's only recommended not to lift heavy things...

I've found that most health-care professionals who do not cycle have no concept of what's involved in a 62-mile bike ride. 'Sure, you can exercise after donating," but they don't realize what type and the length of exercise you plan.