Jack Dorsey, Twitter founder and Square CEO

Being at the head of two exciting tech startups doesn't leave too much time for rest. In 2011, Dorsey told Kara Swisher that he was spending 8-10 hours a day at Square, and 8-10 hours a day at Twitter.

That left him somewhere around four to six hours a night to sleep, possibly less when travel time is factored in.

Sep 21, 2012

Executives who barely sleep

These famous people have shunned the eight-hour mantra and managed to rise to the top.