My sleep habits are very consistent. I crash quickly at 11 PM and at 2 PM. Seriously, I can tell what time it is by how my brain feels. That 2 PM part makes it hard to think about getting a real job, but it helps me skip the hottest part of the day in summer. Meanwhile, I have a hard time staying in bed past 4AM. There was a time when I could work way into the wee hours of the morning, but I probably didn't get enough sleep overall. Can we change our natural sleep schedules? We have to, to accommodate jobs. This TED-Ed lesson explains circadian rhythms and what we can do about them.