My hours of efficiency are not like in grandparent, and after I'd tried a lot of things with switching the sleeping time, the only conclusion that these hours a

My hours of efficiency are not like in grandparent, and after I'd tried a lot of things with switching the sleeping time, the only conclusion that these hours are tied to internal clock of what is day/night (1 to 10 a.m. for me, varies a bit in winter/summer). I know two ways around: constant jet lag or submarine mode, and can't go for any of them.