Dr. Michael Breus writes on the Insomnia Blog that to find your perfect bedtime, you should count back 7.5 hours from your typical wake time (the average person has 5 sleep cycles that last 90 minutes long, so that’s why we should start with 7.5 hours). If you wake up within 10 minutes before your morning alarm after three days, that’s your target bedtime.
If not, move your bedtime back by 15 minutes every three days until you do wake up just before your morning alarm.
Imagine waking up without needing the alarm clock—and getting the sleep you need. That is definitely worth this little experiment.
Is Your Bedtime Making You Fat? [The Insomnia Blog]