According to Russel Barkley (well known and central figure in the ADHD scientific community), you should definitely take short breaks every so many minutes.

He recommends 3 mins for every 10 minutes of work, but that's for children.

I think you'd want be interested in watching this video https://www.youtube.com/watch?v=_tpB-B8BXk0

Definitely check out his other work as well, listening to his talks is like reading my own diary... except translated to scientific language