It would really be neat if a member came in, knowing nothing about the OP and told him everything he assumed about his training. Oh wait......
Seriously, some guys actually have what is called a build up of fitness, and can train both intensely AND for a long period of time. What happens is that about an hour into a tough session, the CNS "beefs up" and sends signals to help the body combat the pounding it's receiving. I REALLY notice it on leg days....where my first 5 sets of squats wreck me, but by the time I've done backs, rdls, extension, curls, and back to hacks and calves, I'm good to go again. This type of volume training is exactly how many of the past champions forged their physiques.
With that said, I also train high intensity, 2 sets of positive failure, and 45-60min sessions as well. Some days though the volume/2 hr sessions are where it's at.
BTW, that whole "science" stating that you go catabolic after 1 hour of lifting is PURE HORSESHIT. Think critically for a moment people. How on Earth is the human body that fragile, not to mention what a freaking arbitrary time frame. "50 minutes is good.....60 is baaaaaaaad." LOL