Some people have a "natural alarm clock" allowing them to wake up when they want. This is actually caused by a burst of the stress hormone adrenocorticotropin.
15
47% of people have a nightmare at least once a month.
186
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
There's a love mattress that is specifically designed for couples who sleep on each other's arms.
12
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13