Why you sometimes wake up tired and groggy ( I do too!)

Ever wondered why you wake up and feel like you didn't have enough sleep  when indeed you did (or like you had a royal rumble match with a lion in your sleep)?

Here's what i found out from wikihow:

source

• When you sleep, you cycle between REM (Rapid Eye Movement) sleep and non-REM sleep. Non-REM sleep comprises three stages: N1 (Transition to sleep), N2 (Light sleep), and N3 (Deep sleep). You usually slip into REM sleep 70 to 90 minutes after falling asleep, and this is when most of your dreams occur.^[10]
• Each sleep cycle lasts roughly 90 minutes, and repeats four to six times over the course of a night. If you are awoken in the midst of N3 deep sleep, you may feel groggy and disoriented. You want to wake during the lighter, more active stages of sleep, especially REM or N1.
• Try setting a wake-up time that's a multiple of 90 minutes away from the current time.

• Consider using a sleep-cycle calculator like [THIS] to plan out the best time to wake.

I used the sleepy time calculator to calculate when i need to sleep if i had to be awake by 5:30am and here's what i got:

You should try to fall asleep at one of the following times:
8:30 PM or 10:00 PM or 11:30 PM or 1:00 AMPlease keep in mind that you should be falling asleep at these times.
The average human takes fourteen minutes to fall asleep, so plan accordingly!
sleepyti.me works by counting backwards in sleep cycles. Waking up in the middle of a sleep cycle leaves you feeling tired and groggy, but waking up in between cycles wakes you up feeling refreshed and alert!

I'm definitely going to use this and see how it works!

Do you have any tricks up your sleeves that you can share with us?