If you are not waking up refreshed, it means you are not getting quality sleep. Hours of sleep are meaningless if it is not quality sleep. For me, it was all about good head and neck posture during sleep. Without it, my sleep would not be refreshing. My wife could look at my sleep posture and facial expressions when I was asleep and tell if I was going to have a good day. My breathing would be irregular, my body might twitch a bit or I might have tense muscles. We used to be able to sleep holding hands but I got so I would squeeze my grip and her hand. I get some of my best sleep in a recliner chair that supports me for good head and neck posture. When I am getting good sleep, my body relaxes completely so even my face droops.

Subtle C-1 and C-2 neck injuries/strains will cause inflammation during sleep with poor posture. This interrupts blood flow and even breathing.