Getting more sleep doesn't mean you'll wake up more rested. Here's why:
Scientist: Michael J. Breus, Ph.D., Psychologist, American Academy of Sleep Medicine
Answer: If you got more sleep than you’re used to last night, then you’re tired because you got more sleep than you’re used to last night.
When it comes to sleep, your body loves consistency. If you usually get 8 hours of sleep, then suddenly get 9, you disrupt your sleep rhythm and throw your body off.
Also, if you add an extra hour of sleep, when your alarm goes off it may be waking you between stages 3 and 4, the deep sleep stage (AKA, the hardest sleep stage to wake from) and doing so can leave you tired and groggy for the rest of the day!
The average sleep cycle is about 90 mins. The average sleeper gets 5 complete sleep cycles in a night, or 7.5 hours. So to figure out your best sleep schedule, start at the time that you need to wake up, and count backward 7.5 hours. That's the time you want to fall asleep to get the full 5 sleep cycles that your body needs.
Read more about why your tired and/or can't sleep. (YouBeauty)