We have couple down here in Bonaire that we are good friends with (retired about same time we did and moved down here full time)  that does crosfitt a coupe times a week. Some brutal stuff. She has Parkinsons and does as much as she can and gives exercise big credit in keeping her Parkinson's symptoms at bay  and her ability to function as good as it can be. Diet being her other main go to that has made a big difference (almost total carnivore) with a few other more minor improvements from exogenous ketones and high dose vitamin B. It takes all of it and regular daily taking care of horses as therapy to keep her functioning at a level where unless a person is familiar with Parkinson's sufferers many people would not notice. That all the way a few years ago of her husband having to carry her to the bathroom because she was unable to walk.

So diet, exercise, staying active both mentally and physically (up at 5am to take care of the horses) and a few medically unapproved supplements are what got her life back for her. She takes NO Parkinson's prescribed medicine because of the side effects and she says it only helps with the tremor symptoms and she can live with that without the medicine messing with her with the side effects.

I write this in case anyone is diagnosed with Parkinson's. There is hope and groups outside the medical system she has joined that has good information about alternative treatment that actually helps instead of just masking the symptoms.

Old geezers who don't consider their diet as being important for their health and quality of life wellbeing are missing the boat, in my opinion.