By now it's no secret that there's a direct link between sleep and work performance. The numbers are staggering: The National Safety Council has estimated that fatigued employees cost employers about $136 billion a year in lost productivity.

"Sleep is so important for us that it can be easily noticed on the days we don't have enough of it," says Alcibiades I. Rodriguez, a professor of neurology and medical director of the NYU Langone Comprehensive Epilepsy and Sleep Center. "You can experience a lack of concentration, attention, moodiness, and decreased reaction time."

You've probably sacrificed a few hours' sleep to send late-night emails, deal with customer requests, or handle any number of other seemingly urgent work tasks. But even once you do turn in for the night, the setup of your bedroom could be costing you additional rest.

Read more at Inc.com.