The cool-down: is it necessary?

We know that we have to warm up before a workout to make sure our muscles don't cramp up. But how important is the cool-down? My fitness instructors always insist on doing an adequate cool-down -- they claim it's just as important as the warm-up.

Still not convinced? Read this post on Fitsugar. The cool-down has a number of great benefits -- it prevents next-day soreness (particularly if your cool-down includes stretching), it helps you increase the range-of-motion in your joints, and it helps keep you from fainting. And as someone who is prone to fainting, I can tell you that it really does help if you walk it off after a run -- I've fainted after not adequately cooling down following a particularly grueling cardio session.