Sleep is important. Not enough of it will make you unproductive and sluggish possibly throughout the next day. And too much of it is a waste of time. So how long do some of the most successful people in the world sleep for? Check it out:

Elon Musk – CEO of Tesla Motors (6 hours)

Bill Gates – Former Microsoft CEO (7 hours)

Ellen DeGeneres – Comedian & actress (8 hours)

Marissa Mayer – President and CEO of Yahoo! (4-6 hours)

Richard Branson – Founder of Virgin Group (5-6 hours)

Arianna Huffington – Co-founder & editor-in-chief of The Huffington Post (7 hours)

Rand Fishkin – Founder of Moz (8 hours)

Tim Cook – CEO of Apple Inc. (7 hours)

Jeff Bezos – Founder & CEO of Amazon.com (7 hours)

Tim Armstrong – CEO and Chairman of AOL Inc. (6 hours)

Benjamin Franklin – Founding Father of the United States (7 hours)

Indra Nooyi – CEO of PepsiCo. (5 hours)

Jack Dorsey – CEO of Square, Inc. & Twitter (7 hours)

Karen Blackett – CEO of MediaCom UK (7-8 hours)

Leo Widrich – Co-founder and COO of Buffer (8 hours)

Barack Obama – President of United States (6 hours)