They only do that for 3 hours a couple times a year, to be fair, although yeah, that's way out of my league as well.
As for the OP... that's a lot to get done. Personally I do one of the treadmill's pre-sets which goes from 3 degrees to 15 degrees every couple minutes and even at 4mph, after an hour (and 1100 calories burned!) I'm pretty well dead. I doubt I'd last 5 minutes on that at 7 mph. The key, I think, is to get your heart into the aerobic area for 20-30 minutes a day, 5 days a week. Killing yourself for 5 minutes won't really do that, unfortunately. It should be pointed out, too, that just as important as losing weight are the effects that a regular aerobic workout has on your heart (which is positive). Also, it's cool to be able to do things like run for several minutes at a time which you couldn't do a few months before.
Weightlifting doesn't really lead directly to losing weight per se but it can improve your metabolism after a while, which means your body consumes more calories in its resting state, which in turn = more weight lost for the same amount of food consumed. That being said, unless you're really dedicated to lifting weights, completely changing your diet to gain muscle mass and all that, you probably can't expect to gain a lot of muscle except over a long, long period of time, like several years worth of lifting.
