The average sleep cycle is 1hr30mins. I think when we sleep for 6 hours, we complete 4 sleep cycles and wake up refreshed. When we sleep for 7 hours, we wake up mid-cycle. At ~8 hours, we wake up before we get stuck into the middle of a sleep cycle or enter REM.
I read this somewhere online, someone who knows more can verify if this is the actual science. If not, it's a fun hypothesis I'll choose to believe :p
Yes, that's true! And at least for me it is surprisingly accurate with 1h30. I started the habit of looking at the clock everytime I fall to sleep and wake up and it is always after 4.5, 6, 7.5 or 9 hours of sleep!
Also I heard that it is better to sleep 7.5 hours compared to 8 hours, because being waken up from deep sleep allegedly will make you more tired than these 30 minutes of extra sleep.
Probably, I used to have an app which is supposed to wake you up at the right part of the cycle. It kind of worked? Stupid body needs to be happy I allocated enough time at all
IIRC, there's also devices you can buy that will literally measure your eye movements while you sleep and only wake you up at the optimal times.
Here's one I found with a quick search: https://somalytics.com/somasleep/
Sadly not yet available.
6 is just OK for me, for some reason when I get 4.5hrs of sleep I wake up feeling like I just downed a litre of coffee.
Sometimes it's like a weird fake rush of energy and then it all crashes after a few hours
6 is amazing until I've done it for weeks on end, then I descend down the chart
