That's not quite the range of the Phantom 3 Professional, which managed 2,500 feet without issue, but it's better than the 1,000 feet I got with the Phantom 3 Standard in open space and the 400 feet it managed in suburbia.
Medical specialists with a public voice like Dr. Oz should absolutely be encouraging people who are sleepy to sleep more. However, arbitrarily applying eight hours to everyone is actually harming people who simply need less sleep, or those who actually need more than eight hours.
REM sleep occurs at intervals of one to two hours, and is variable in length. REM sleep is characterized by irregular breathing and heart rate, and involuntary muscle jerks. Most adults need around eight hours of sleep on a regular schedule to function well, although some require less, and others more. (It has been said that men need an hour less sleep than women.) Children, particularly teenagers, often need nine or ten hours for optimal functioning.