It depends on what phase you wake up in during your sleep cycle. If you finish your 90 minute sleep cycle and wake up around then, even if it’s only been 3 hours, you won’t feel as tired as of you wake up in the middle of your REM cycle, even if you have already slept 7+ hours.
Also some people need more sleep than others or are on a different sleep cycle (variations of naps during the day and less time at night)
Latest Answers