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.
To do this, figure out what time you need to get up in the morning. Count back 7.5 hours as a good time to start getting to bed. 7.5 hours is a good benchmark because the average person goes through five 90 minute sleep cycles alternating between sleep (non-REM) and deep sleep (REM). It's best to wake in-between deep sleep cycles rather than in the middle of one.