Fast Company asks: Do you know how long it takes to get into your best frame of mind to focus?

Figuring out what time you should wake up is important, not only to optimize performance, but also to maintain good work-life balance, says sleep expert Teofilo Lee-Chiong, professor of medicine at National Jewish Health in Denver and the University of Colorado School of Medicine.

“We all suffer from a certain degree of sleep inertia—that feeling that makes you want to continuously hit snooze in the morning,” he says. “Someone with pronounced inertia has a strong desire to return to sleep, and morning sleep inertia and its impairments to mental alertness and physical functioning can last anywhere from two to four hours.”