So we go through in the beginning of the night, we go into the really deep stages of sleep and we actually cycle through. So, when you go down to the deep stage, then you go back up and you actually come into something called REM sleep, which is after about 90 minutes.

Narcolepsy is a disorder that affects many different areas of life. So in typical patients with narcolepsy, they have something called "excessive daytime sleepiness." So, they're very sleepy during the day. Yet, at night, they're still sleepy, but their sleep is very broken.

Really if it's an hour or two after you've fallen asleep because you're in such a deep sleep at that point.

So when it comes to circadian rhythms, it's a clock that's basically programmed in our body. So if you think back to times when people lived on farms and we didn't have electricity.

So we go through in the beginning of the night, we go into the really deep stages of sleep and we actually cycle through. So, when you go down to the deep stage, then you go back up and you actually come into something called REM sleep, which is after about 90 minutes.

Decrements in attention and concentration, being able to learn more efficiently, that's just not as good. Also, there are motor vehicle accidents, workplace accidents, we see that a lot.

So the deeper stages of sleep are really those times of quiescence, you're really restoring your body and we have a few different stages of sleep.