I was severely sleep deprived for about 20 years. I was a truck driver for 10 years, then went to school to get an engineering degree. Usually got about 2 hours of sleep a night at most during that whole time. When I got a normal job, I started sleeping 6 hours a night, but still felt the same. After way too long, I got checked and I have really bad sleep apnea (104 apneas per hour). Now that I am on a CPAP, I sleep 6 -7 hours a night, and feel pretty good all day.
I need to try to figure out how to bump that up to 8 hours, but I just don't have the time to do it. I am a powerlifter, and the extra sleep would really help me.