How much do your muscles swell after a workout and how long until the swelling goes down?

depends on many factors. How well dehydrated you are, your build and physiology, what kind of work out you are doing etc... I know after an intense work out with weights I am very impressed with how my muscles look but they will loose the high amounts of blood 1 to 2 hours after the work out, I can look 20 lbs heavier at the end of a work out than I did at the begining of the same work out.

45 minutes