There’s an interesting study in the New York Time today that looks at the effects a high-intensity workout has on your body after your workout has finished. In particular, the study looked at how many calories the body continued burning long after said workout was done.
The answer: for a high-intensity workout that burned 420 calories, 190 additional calories were burned over the following 14 hours. Pretty impressive if you ask me. Of course there are studies that will say this number is way off the charts, but I believe there are definitely positive aftereffects that come from an intense workout. (Not even counting the cardiovascular benefits.)