Based on the information I'm always given when I donate blood, I would say you shouldn't suffer any ill effects. They tell me not to do anythng streuous for 5 hours after donating. Last donation I made I rode 36 miles the next day, which was a new long distance for me, and I was fine.

Ask your doc of course, but it it's just blood drawn, like for blood tests, it's not nearly as much as the pint plus testing vials they take when you donate.