It depends on the meaning of "lot"

A few minutes ago on the phone with a friend, currently a resident at a prestigious Texas hospital:

I'm getting three to four hours of sleep a night. That's a lot.

Mrs. SC:

No, it's not. Residents at my school get more.

One can easily imagine constructing a scale for "lot" as a modifier for "sleep". For most of us, "a lot" of sleep is probably 7-8 hours a night, "enough" maybe being 6-7, "not much" as 4-5, etc. This is a good reminder that meaning can be context dependent -- when Mrs. SC says that her colleagues get "more" sleep, your host feels comfortable guessing that it's in the range of 0.5 - 1 hour more. Just thinking about getting that little sleep is making SC tired.