Me personally, I say it depends on what your goals are.
If'n yer tryin' ta lose dat dere fat, then you can do whatever, just as long as you keep your heartrate at a decent pace, because the higher your heartrate, the less your body is going to be efficient at burning fat cause you'll be pushing yourself into an anaerobic state (that's all of what I know , I may be wrong, so correct me if I am anyone). So your body doesn't care either what you're doing for exercise as long as you're getting it, and you're doing it in a way that will give you the results you want.
Yeah running is more strenuous form of cardio, and that's great if you're trying to increase your cardiovascular system for whatever reason, but not really for fat loss. For max fat loss, it's best to do AM empty stomach cardio to hit the fat stores, and do it for longer periods at a lower pace. I used to be against the AM cardio thing till i realized that it definately is better for losing fat once you realize that A: The body wants to burn glycogen for energy, B: In the morning, your glycogen levels are rock bottom meaning C: Your body is going to burn fat like a mofo at this time for energy.