Basically seems like a sound article to me. Couple of things to comment upon:
Personal anecdote: I regularly work out for about 2 hours at a time. No, it isn't making me fat. I am thriving on it. But I only work out about 3 times per week, maybe 4. So, the advice in this article is good, but not necessarily universally applicable. We still have to pay attention to what works for us.
Research: I just read an interesting article on over-training targetting runners and it also mentioned the brain/mind effect. i.e., you may be over training if you are getting muddled, foggy thinking, unable to concentrate, etc.
They ran an experiment in which they had a control group of runners averaging a healthy mileage per week, and another group whose mileage was doubled. When they conducted cognitive testing after these exercise bouts, the group who had endured doubled up training scored significantly less well than those in the control group and complained about lack of concentration. Exercise is supposed to make our minds sharper, not cloudier!
More food for thought.
Clare