I was diagnosed in Jan 2017 the day before my 55th birthday, after a year of some mild memory loss that kicked off some scans and tests, that culminated in being confirmed as PD. Lack of movement and rigidity on left hand side, slight dribbling but nothing that people would notice. Left arm dangles when walking (although I can actually move it if needed). Some slow response on left hand when doing fine motor skills. But all in all a very early diagnosis with limited symptoms. No tremor.
I am on 6 x 62.5 Sinemet about to move to 9, as has made only modest difference.
I am a keen triathlete, doing my 4th Ironman in 3 weeks from now, and did a half Ironman in training last month. Not as fast as I used to be (and even that was slow!) but still very keen to take part. If you want to share notes re long distance swimming/cycling/running, get in touch!