All 361 people taking part were given conventional treatments appropriate to their level of depression.
But for eight months some in a randomly allocated group were also given advice on up to 13 separate occasions on how to increase their level of activity.
It was up to individual patients what activity they chose to increase and by how much.
All this proves is that
advice about exercise doesn't help anyone. Most patients want to please their doctors (= authority figures) and some would definitely fib, "Oh yes, doctor, I've been running every day". I wouldn't pay much attention to a study of this kind unless the test subjects were routinely rounded up for half an hour of vigorous
supervised calisthenics.
Exercise, cutting out junk food and reducing a couple of bad habits definitely make me feel better. What a shame that doesn't motivate me to stick with it!