I haven't read the paper, but what I am curious about, how much of the damage can be turned back if someone becomes physically active after a long sedentary period? Let's say someone already had low fat oxidization and/or cardiovascular disease, how much of that can be "cured" by being active?

This post claims: the good news is, this is reversible. But is that so? Is it also proven to reverse things in all cases? I would imagine there are caveats, and things are not that rosy in reality.

The reason I am asking because if the answer is "None. It can only keep the symptoms from worsening" then it's not really reasonable to expect people with such physiological situation to become active again.

They will most probably need to put in much more effort to achieve much smaller gain compared to a healthy individual, which is as I said is unreasonable. Especially because some people simply have worse genetics and or social circumstances which they might not be able to change.

So I appreciate these findings, but how I read this: you need to be aware of this to prevent the ill effects. And I doubt the reversible claim (although I have not much of an argument to corroborate that).