Sometimes people make fun of fidgeters and pacers. Well, I've got something for you who pace and fidget. I heard on the news over a year ago, maybe two about some studies that were done mentioning how exercising can improve mental capacity. Maybe that relates to restless legs or pacing.
Taking that into consideration, it would make sense that exercise or movement, no matter how small must matter to some degree. So if one were to fidget or pace around in circles talking on a phone they may be enhancing their phone conversations by accelerating their mind.
With this theory in mind that exercise and moving may help the mind, it seems you could use more deductive reasoning to conclude that when using the mind (thinking, conversing) the body may react to provide energy for the current thinking process, or to build energy for the future thinking processes assuming that there will be more of the current action and next time will be even more prepared.
Disclaimer: This is my opinion, do not trust my opinion unless you do your own research no matter how much sense something I say makes and I must say ALWAYS seek a doctors opinion ALWAYS so this way I'm not liable in case someone decides to "pace" a little too much and pace right off the top of the Empire State building or something else really terrible.
This is my way of defending fidgeting, pacing, and restless legs against modern science trying to strip us pacers of our dignity. Hehe. Also, if this isn't the reason for the restless legs syndrome, then my opinion is that it's lack of exercise (which based on previous paragraphs may lead one to believe that because one must think and for health purposes exercise is required, then the body may force exercise on its most powerful opponent, best friend, and greatest lover [the mind]).
Here's the only link I found related to this on the web: http://medrants.com/index.php/archives/921
I only searched for no more than 2 hours for the original article I was inspired by. Apparently exercising for health reasons isn't as popular as exercising for 15 pack abs.
The original news report that inspired this article was not found by me, otherwise I'd love to link to it. If you know any more articles that link mental health to physical exercise of any form, please feel free to share them here. Thank you!
PS. Have you ever noticed that when people are fidgeting, they're usually in a thought? It seems to happen so frequently in unison that it almost seems natural (not necessarily necessary?), I think.