I’m 7 years post Parkinsons diagnosis. In the past year, I began having similar symptoms of difficulty in breathing and exhaustion which would begin about an hour after finishing exercise. It took a few hours to abate. My pulse, BP and labs were relatively normal but I still couldn’t breath after the usual post exercise recovery time. My cardiologist tried to simulate these episodes on a treadmill. There were some episodes of atrial fibrillation which was regulated with oral meds for arrhythmia and anti-coagulates. A TBI caused me to discontinuing the blood thinners. Unfortunately the symptoms of breathlessness continued particularly 30-60 minutes after swimming. The likely diagnosis was “sick sinus syndrome”. We decided that an implanted pacemaker was the best option. Since that surgery, I have had no delayed post exercise fatigue. Always wondered if anyone with PD has similar issues.