I have gotten back into training after a few years off. I was wondering if my growth hormone release would be impaired by my lack of sleep? I get about 7 hours a night, but I have an office job where I do a lot of sitting. Is it possible for me to gain mass on 7 hours of sleep a night during the week and 8 hours of sleep on the weekends? Or is it imperative that I get 8+ hours of sleep?