Amount of sleep I’m getting

I’ve noticed myself sleeping around 10 hours on some days (technically, it’s more like 1 hour of trying to fall asleep and 9 hours of actual sleep ). Some days I sleep around 8 hours. In both situations, I wake up feeling rested, so I see the number of hours I sleep as what my body needs that day.

The problem is that I prefer to sleep no more than 8 hours because I plan my days so that I have more time in the morning before work. When I sleep for 10 hours, my mornings become tight and I have to change my plans. I also feel a sense of shame for sleeping longer when I can function fine on 8 hours of sleep. A part of this is also related to my thoughts about being up earlier: I don’t like getting up when it’s still dark out, so sleeping for another 2 hours ensures I wake up to the sun.

I’ve tried a few ways to get myself to sleep for only 8 hours, but in the past few days I’ve turned off my alarm and immediately (on auto-pilot) went back to sleep for another 2 hours. I want to disrupt the moment between turning off the alarm and falling back asleep. I also want to let it be okay that the sun isn’t out when I get up at my ideal time. A part of me also wonders if my body just need 10 hours of sleep, to stop resisting it, and adjust my schedule to allow for that.

Can you help me think about how to approach this?