Then read these 40 amazing sleep facts from Austrailia’s National Sleep Research Center.

Here’s a sampling:

Anything less than five minutes to fall asleep at night means you’re sleep deprived. The ideal is between 10 and 15 minutes, meaning you’re still tired enough to sleep deeply, but not so exhausted you feel sleepy by day.

To drop off we must cool off; body temperature and the brain’s sleep-wake cycle are closely linked. That’s why hot summer nights can cause a restless sleep. The blood flow mechanism that transfers core body heat to the skin works best between 18 and 30 degrees. But later in life, the comfort zone shrinks to between 23 and 25 degrees – one reason why older people have more sleep disorders.

Diaries from the pre-electric-light-globe Victorian era show adults slept nine to 10 hours a night with periods of rest changing with the seasons in line with sunrise and sunsets.