Exercise is o so important, when and if you can. However PWP eventually "freeze-up" and exercise becomes not only naturally difficult, but you don't seem to "heal-up", so that in the next ensuing days and weeks you don't seem to feel the same as you did (that "alive" feeling) when you exercised when you were younger.
Vigorous excercise can make muscles sore and "tight"; so much so that the next day you can develop dystonias, and feel worse for the effort.
Now, is is "worse", well once again it's a function of advancement and general debilitation. If you can barely move and are near the end, exercise is an "impossible" thing, and I think contraindicated at advanced stages (too much of a risk in breaking bones, or pulling inept musculature on a fragile bone structural frame.
So, exercise is wonderful, if you can, but as you get worse to the stage where excercise hurts more afterwards, and keeps you in bed hurting the next day, just take it easy. Non-translational exercise (calinstetics, (sp?)) is useful to keep up the tone of muscles enough to do the things that are personal and neccessary in a day. And always try to get up off your butt and stand for as long as you can in a day without hurting. And (maybe I shouldn't say this as it's like the hog telling the piglet he's too fat) keep those pounds OFF. It's embarrrassing when they have to get an extra orderly to move your bod from one position to the other to get you to fit into the MRI
And parkies getting fat due to low excercise levels and bad nutrtional choices is a whole other thread that we haven't discussed here yet. WE did briefly in the old forum.