I recently made a conscious effort to get back on my bike. I recently began doing other exercises at the expense of riding. In my opinion all exercises helps but cycling is the best.A couple of years back I almost had an opportunity to participate in a clinical trial at the Cleveland Clinic. The trial measured the benefits of high speed cycling on pd. I have focusing on riding within the protocols of the trial and it really helps. Here is my challenge, If you have pd and are able to pedal a bike 80-100 rpm for at least 45 minutes. I know this is hard.The research also works for tandem bikes. I guarantee you will feel better immediately. Comment me and let me know how it works for you.