After 51 years of sleep deprivation, I was diagnosed with Sleep Apnea. My body stopped breathing hundreds of times a night, and woke to save my life. Not very conducive to restfulness? I am not hooked to a machine which keeps a continuous flow of air going into my body through my nose. The mask fits over the nose. It ain't pretty, and I am not supposed to open my mouth when I'm in bed. (My wife loves that!) I sleep better these days...Just a few other problems I need to handle.