
Originally Posted by
2Sox
From my personal experience with this, dehydration is the main reason people feel like shit after a blood donation. Your donated blood is mostly water. When you generously hydrate before and after the procedure, you'll feel like nothing happened. However, I would advise that you refrain from very strenuous activity the day of your donation. No matter how much you hydrate, you WILL be weaker than usual. I made the mistake of going out dancing on the evening after a donation and my legs felt like lead.