Absolute nonsense - people are different. I trained myself to wake up at a certain time whilst in busy jobs and often I sleep no more than just under 5 hrs. I can have very short and refreshing sleeps (10 minutes) during the day. I am not bi-polar, an early riser - tend to relax at night, but often do my writing, correspondence, also TV at night only. I have met a number of people who can do with much less than 8 hrs per night - it probably depends on the quality of the sleep, too.
Never go to bed on a full stomach: have your evening meal early and eat lightly and no snacks - I allow myself one alcoholic drink at times (not every day), but also not before going to bed.
