This is a different take on cycling and PD. Personally met this chap, he looks amazing, and is doing very well. He tells of people who have difficulty walking but who can do long distance cycling, and is a powerful advocate for exercise, in every way.

http://pedalforparkinsons.co.uk

On another note, while exercise is known to be good for us, and to increase stamina, help with many things PD, and actually I love walking and being active, and especially love gardening, what do you do if fatigue is one of your symptoms. I often have very active days especially in warmer weather but pay a price, a little too much can result in a couple of days that are completely energy free........