I'm glad you asked this question. I've been toying with trying to donate blood again. I have donated in the past, but I haven't in a very long time. I usually get physically sick after donating. It lasts weeks. I think it kills my immune system or something. It just zaps me, so I stopped donating.

That said, I'm much healthier now and I want to give it another try. BUT, I'm currently training for a half-marathon and I can't afford to get sick and be down for a few weeks.