So a lot of people who work rotating shifts and they work at night, their bodies are set to want to be awake during the day and sleep at night. So there are some people who have a lot of trouble adjusting their rhythms and they have trouble working the night shift, they're sleepy, they're drowsy driving home.

Well, the actual function of the brain, not so sure yet. There's a lot of different theories about it, but when you talk about psychologically in your brain, a lot of people with insomnia, though not all, report that they can't turn their minds off.

Now circadian rhythms become very interesting and problematic for patients because when you become a teenager, your rhythms actually tend to naturally shift.

We haven't really - it's harder for us to set those rhythms. So it's really important to keep a steady bedtime and wake time to really lock in those rhythms.

We actually don't know the function of sleep all that well yet, but sleep is a time of quiescence in the brain.

So the older models, when you look at Freudian, when you look at Jungian thought, and there's still people who really - who really use the Jungian thought of dream analysis, is really that you would analyze the dreams. The dreams are there for a purpose.

When you are more awake at nights, they'll toss and turn, they'll think more, they get frustrated. And when that starts to happen, you really don't sleep even more because you're making your body tense and your mind is getting more and more active.