Sleep doctor Michael Breus discusses chronotypes with Forbes.

So if you’d ever heard of somebody being called an ‘early bird’ or a ‘night owl’, those are chronotypes. But it turns out that there aren’t just two. There’s actually four. I was able to create an assessment tool if you will, quiz, that people can take online. So for folks out there who want to figure out what their chronotype is, it’s free. Just go to and you can absolutely positively figure this out. You can learn which one of the four chronotypes you fall into.