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
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
There's a love mattress that is specifically designed for couples who sleep on each other's arms.
12
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15