I think this has been touched on recently but I can't find the thread so I thought I'd raise the question again.
I've given blood before (though not since I've been cycling) and wanted to do it again, especially as it seems to be the only way to find out your blood type.
However, I'm sure I've read somewhere that it affects (or effects pedants??) your ability to exercise fully for some time after.
Is this correct? If so, I may wait until later in the year to do it. I can't afford to lose any more fitness!!