One: Donating blood will reduce your volume. Stay on top of your hydration before and after.
Two: Donating blood may make you feel drained. Stick to recovery rides the day of and after.
Three: Thank you for looking out for and helping others.
Great to hear that you’re considering donating blood!
You should recover from the volume loss in 24-48 hours, assuming you hydrate well.
The red blood cells take longer to recover. I’ve seen some suggestions that it can be up to four weeks to fully recover, with a mostly complete recovery after two weeks. My experience has been that I’m feeling pretty much back to normal after a week or so. Some more information is here: Say I Donate Blood. How Long 'till I'm Back to Normal? | Runner's World
You’ll be able to train, but your performance will be reduced until you get the red blood cells back.
These days I donate platelets instead of whole blood - it takes longer at the blood service, but the recovery (from an athletic performance perspective) is much quicker.
I like to donate right at the start of a rest week, since I am generally not doing any MAP/AC/NM stuff for a few days. I find I can do Z2 pretty well at the end of that first week, but it takes me a bit longer (another week or maybe two) to feel good at full throttle for any length of time.
Also, since I am O+, they encourage me to give double red during each visit. I did it once and it took me a full month (at least) to get over that one. Don’t recommend that without building it into your plan!
Still remember one time I gave blood and the next day I was doing a fast run at the gym. Started to feel nauseous and extra hot and clammy and a bit light headed. Had to tone it down. 2 days later I felt fine. So, usually just have to take it easy for the next 24-48 hours.
First thanks for donating. I have been giving blood since 1973, Yeah I am old! The posts above cover it pretty well. Be well hydrated and get plenty of fluids for the few days after. I have moved to Power Red donations. Here is the blurb from the American Red Cross.
With a Power Red donation, you can give nearly twice the amount of red cells and help more patients. This type of donation uses an automated process that separates your red blood cells from the other blood components, and then safely and comfortably returns your plasma and platelets to you.
You can only donate half as often but still give the same amount of benefit. I find my recovery from this kind of donation to be very fast, 24-48 hours only. No problem doing a recovery ride the same day although they frown on it.