it all depends, if you can do it without sleep, have an effective workout and then be able to rest properly afterwards, I think you can get away it; I do it a lot off and on cycle. If you're someone that needs their rest for that period of time, then I would sleep and recover. However, it all depends on how you feel just, from personal experience I'd go with it, get in a great and quick workout, eat and rest after that and you should be alright. Plus when that hella's in full effect, even through to PCT, some days will be better than others and since everyone is different, some may agree or not, but 6 hours of sleep on with a decent diet on top of working, playing, staying active is more beneficial, but you may or may not get more energy and feel better overtime.