Exercise, definitely exercise.

I think that exercise is what has kept me relatively stable for the last two years. I work out three or four times per week, 35-45 minutes, mostly vigorous cardio, and some weight training.

This is something that I started - well, my wife got me to start - about 2-1/2 years ago, and I've kept it up since. I hadn't been diagnosed yet, but there was one day in which various odd things that I had noticed for several years all came together at the same time. We went on line and looked at all the various things that had tremors as one of the symptoms, and they all said, "Exercise helps!" (Also looked at the whole list of Parkinson's symptoms, and we said to each other ,"Uh-oh, this doesn't look good.") My wife went out the next day and got us both memberships in a gym.

There were several weeks of MRI's and neurologist visits, and a steady increase in symtoms, before a diagnosis was made. Since then, after having had that one-weekend severe increase in symptoms, and getting stabilized on a given set of meds, I have required very little modification or increase in medications. Now, I know that it is partially due to the perverse nature of PD that things have stayed stable, but am just as certain that the exercise has made a big difference in slowing it down.

One thing that I do is exercise in the evening, after work, instead of in the morning. I also found that the morning was far too tiring, and I ended up sleeping it off for the rest of the morning.

So, go to it, and good luck to you. At 21, you've got a long uphill row to hoe, and might as well do all you can to cut the hill down to size.