I probably average about 5-6 hours a night, can be much worse at times, which long term IMO is pretty bad for ones mental health (there is actually some evidence to suggest prolonged lack of sleep can cause perma brain cell loss.) It seems to not affect my gym performance at all though, I can do incredibly intense 2 hour long workouts everyday during a week where i only got 4-5 hours sleep a night... mentally though, for the most part, I just avoid anything that requires too much thought LOL.