It's possible. There seems to be a lot of individual variability around this threshold, although as usual the problem is a severe lack of data on the effects of

It's possible. There seems to be a lot of individual variability around this threshold, although as usual the problem is a severe lack of data on the effects of partial gravity on anything. Alan Shephard and Ed Mitchell reported that the 7 degree tilt of their lunar module interfered with their sleep, which suggests it was noticeable. But it would be hard to point to something in their cabin arrangements that didn't interfere with sleep.