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.
How much time are you in bed at night ? If you are giving yourself opportunity to sleep for 8+ hours at night ( no phones, no tv, no light, no stimuli ) and do you feel rested in the morning once getting up for the day after 8+ hrs in bed giving yourself opportunity to sleep, yet dream in 15 min long naps during the day. Do your self a favor -.