The Orienteer,
Welcome to HealingWell. Glad you found this site.
First of all, no two people with PD respond the same to types/dosage/etc of meds. Sinemet is known to address symptoms the best. However, as with most meds, it can have side effects. Educate yourself on the side effects. My preference is to start out on other meds and save Sinemet for later.
You are your best advocate. Educate yourself on meds, dosages, side effects etc. My preference - and that of many newbies with PD - is to start out on a dopamine agonist such as Mirapex or Requip. There also is a patch -rotigotine, that has proven effective for many. My preference is to delay Sinemet until I have exhausted other alternatives. Others on this site are more favorable about taking Sinemet earlier in their treatment plan. The important part is to educate yourself and take an active role in your treatment plan.
I am a believer in the benefits of exercise. I have participated in a non-contact, boxing-based fitness program for people with PD since 2006. In fact, I am one of several in the class ending a 2-year study comparing rigorous exercise (like my class) to physical therapy. Results are not officially available, but indications are that it slows the progression.
I am not a runner (simply because I don't like to run), but know runners who are not that affected when running. They (and I) notice more challenges when walking than when running. When I walk, I have to think to take a big step and heal first (rather than 'slap' foot on ground). When I run, it just comes together without thinking about it. So it's interesting that you notice it when running.
Best of luck!
lizzy4451