The most productive days at work are typically the days with the least breaks. That makes sense, right?

Well, apparently not. Our brains can only operate at full speed for so long before their capability starts to slip.

The Basic Rest Activity Cycle, also called BRAC, describes the normal human sleep cycle, which is approximately 90 minutes in length, where we gradually descend into REM sleep and then begin the process all over again.

Apparently, our brains when we're awake are not all that different from our sleeping brains—they function on cycles round the clock. Because we need time to recover between cycles, it's best to work in 90 minute periods with intermittent breaks.

Why is it I'm more productive on my ten minute breaks at work rather than the hours I have at home?

— R. K. Brainerd (@awakedragon)

While it may seem like there's zero time to take a break some days, taking even a few moments to decompress can increase productivity in the long run.

Professor K. Anders Ericsson and his colleagues at Florida State University have studied elite musicians, athletes, actors and chess players.

"To maximize gains from long-term practice, individuals must avoid exhaustion and must limit practice to an amount from which they can completely recover on a daily or weekly basis," Ericsson told  The New York Times.

A photo posted by @zielsk0 on Sep 2, 2014 at 5:58am PDT

Essentially, catering to the natural ebbs and flows of the brain is the best way to get the most out of the work day, or really any long-term project.