I have been watching the tennis and one of the things the players are great at, is resting. Between each game they sit, they grab drinks and snacks, they change clothes, and they rest.
I read a study a while back that breaks are often most effective just before you hit peak productivity. The idea being that resting and/or fueling up before you get to your best streak, gets you a better streak.
Now I realize not all jobs allow you to be like, oh I think now is the best time for me to break. But it's easy to be like if I stay here and keep going, I'll stay in the zone. To treat getting up for a snack or a bathroom break as distractions, instead of things that support your body and mind and help you continue on.
But as the Tony award winning Broadway show said, take a break. Okay, I realize posting this on a Monday is a little mean, but plan your break today, if it isn't time for it yet.