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.
If you continue going to bed at the same time and allowing your body to wake up naturally, you will eventually establish a pattern of sleeping essentially the same amount of time each night, probably in the range of 7 to 9 hours. Congratulations! You've identified the amount of sleep that you need.