Do you find your sleep skews? Any longer (2-3 week) vacations I've taken I've found that my waking up time keeps skewing even if I'm not going to bed later. Maybe I've never seen the end where it stabilizes.
My sleep cycle naturally drifts infinitely by some 30 minutes a day on average.
It makes life strange at times, especially on this latitude. Imagine waking up at night through a whole winter, not seeing the Sun for months.
I've tried to hold steady cycle but I just grow more and more tired every day until finally the alarm fails to wake me. School was hell. Was absent a lot simply for sleeping.
I was exactly the same, a lot of reading about sleep and strict sleep hygiene fixed it. There are lots you can do but briefly just go out for a jog when you wake up. You need the exposure to blue light to help set your circadian rhythm. The exercise increases body temp which helps bring forward your circadian rhythm.
Basically your habits are probably shifting your circadian rhythm back 30min a day, and if not you can have habits which bring forward your circadian rythm
My wake up time is a 2 hour window between 7:30 and 9:30 but usually around the middle of that. It varies day to day. Whether it's earlier or later mostly depends on how much exercise I do the day before. My training has large spikes where I go out rock climbing all day and then have multiple "rest" days so I let my body get whatever sleep it needs.
At the beginning of the pandemic, no one in our family had any fixed time obligations other than my afternoon meetings, so we basically stopped enforcing any bedtimes or wake up times for the kids (and ourselves).
Pre-pandemic we were all waking around 8am to get my daughter to pre-school. Within a week of foregoing bedtimes, we were all going to bed between 2am and 4am and waking up around 11am. So the kids still got their 9 hours and the adults got their 7, but it did stabilize.
There are so many variables involved, once you start listening, the schedule will never be a schedule again.
Sometimes I want to sleep a few extra hours. Sometimes I'm so excited for the day, I get up early and go to sleep late. Sometimes I need to stay up for a while, and next time I sleep it's for 20 hours straight. Sometimes it's just a nap here and there for a few days.
The most important thing I've learned is to listen to my tiredness level, and not get too carried away with productivity.
My waking times definitely skew, but for me I think it happens because my bed time pushes it later and later until my night owl habits and my guilt over sleeping late reach an equilibrium.
When I was in college I'd pretty quickly drift to a 4:00AM to noon sleep schedule on holidays. Even today (in my mid 20's) I find I'm happiest sleeping from roughly 2:00AM to 10:00AM.
My sleep cycle naturally drifts infinitely by some 30 minutes a day on average.
It makes life strange at times, especially on this latitude. Imagine waking up at night through a whole winter, not seeing the Sun for months.
I've tried to hold steady cycle but I just grow more and more tired every day until finally the alarm fails to wake me. School was hell. Was absent a lot simply for sleeping.