I'm sorry, but that's the most idiotic and ignorant thing I've read in a while. 4-5 hours of exercise every day? That's definitely NOT healthy, especially for someone whose base fitness isn't good. That's way, way, way, WAY too much exercise in such a short timespan. Your body needs time to recover. What you describe here is way too much even for professional athletes. Complete and utter insanity. You'll end up with severe chronic fatigue and all kinds of health problems.
That said, I'm in a very good shape and regularly go running (4 times a week). This has no effect on my DR whatsoever.
Agreed. If exercise helps people, then by all means they should go for it, but exercise alone is not going to cure this, and 4-5 hours of exercise is unrealistic and can be dangerous. Depersonalization stems from anxiety and trauma, which for some people can be really complex, and people really need to stop with the "Doing this ONE thing will cure you" type of posts, becasue there is not one cure for everyone.
I unfortunately have Chronic Fatigue Syndrome and fibromyalgia so exercising intensely for just 20 minutes can literally make me bed-bound for the next few days after. Definitely not gonna try this "cure" anyway XD