I'm not certain they NEED more --- they just always seems to be on the move. My oldest daughter has ADD, but she is not hyperactive.

Need more than the average person? I don't think so.

There may be something to exercise helping focus, or helping to tire out, but I don't think its a need.

I was diagnosed with ADHD. Exercise always helped me relax.

I had a couple kids with ADHD, and looking back, I was probably ADHD and no one knew or cared. I think if anything, ADHD kids don't have any problem getting enough exercise because they are already active (if you let them). For things like studies, though, I noticed that our older son studied better if he ran around the neighborhood a couple times before he sat down to study something. He also turned out to be a state champ wrestler.