To learn more about what's happening on the International Space Station at any given time, check out NASA's frequently-updated ISS blog or their page about the research and development work happening on ISS.
Depends on your body type and metabolism and your routine. But usually it takes around 3 to 4 weeks for visible results. For me it took me a couple of months to actually see any progress visually.
However, in the future, I think I will just be on the safe side and make sure I take it easy before I have any blood work done. As a matter of fact, it is recommended that to get the most accurate blood test results, patients should not exercise for 24 hours before a blood draw. So, take that advice as an excuse to take a day off and relax before your next physical appointment.