Restlessness is the most anti-productive feeling. It is only beneficial for people who are just put on work to show restlessness to get work done. Also, that is a very bad way to get work done. It is sometimes seen as positive for organisations with small goals – like an outsourcing company at a certain project stage but is generally very bad for long term.
In restlessness, humans keep getting burst of moments when they can be productive and can focus on a particular thing. Then restlessness superseded all the thoughts. Its like heartbeat, but the duration is little more than that. In those small moments, if a human is super performant and self motivated, he tries to snatch every second to put to work, but such is a misery of restlessness that it takes him over. Then after some time, he has a chance to take over. Distractions occur very easily and humans might end up with just one or two moments of productive work.
It is generally never seen that people actually observe themselves in such situation or take some time to relax. Rather they would be eating, drinking or smoking in breaks. Deep breathe generally helps as it lowers blood rush. A low blood rush helps in focussing and focussing helps maintain that low blood rush. Similarly stress brings restlessness and restlessness ensures persistent stress. What works again is detaching yourself from moment, observing you as such and then getting back after correcting.