There's actually some studies starting up that are trying to confirm a theory on if the restless leg and other hyperactive movements are a means of self treatment for ADHD. Seems plausible to me, tbh.

They think lactic acid might play a role in the brain, and ADHD people are lacking as a symptom of ADHD. And since lactic acid can be produced in the muscles through exercise/movement, the theory is that by being hyper active, it creates the lactic acid which gets transported to the brain as a type of subconscious self treatment.

Kinda fascinating, tbh. Especially so, given that my body is currently twitching/bouncing from restless legs in my chair as I type this. Lol The best I've ever felt in my brain (and body) was when I used to heavily workout 6 days a week and was constantly sore from the lactic acid buildup. I think these kinds of studies are an interesting premise.

https://pubmed.ncbi.nlm.nih.gov/30550949/