One other thought. Unrelated to heart. To reduce sluggishness I:
1. up my carbs
2. rest as needed
3. strengthen my legs (light weights with lots of reps).
4. strengthen back muscles (pull downs).
Once I have done the leg work, it takes a couple of weeks to recover and get back to normal. Running is really difficult during that period. In the end though, I find after recovery that time and distance improve.
Of course a doctor could tell you more, but I did learn at some point that there is some thinking out there that says PVCs like this could be caused by stretching of a papillary muscle.
There are other possibilities too, but the reason I mention this one is because I was recently diagnosed with this issue (in my case benign VT), and as it turns out have very similar symptoms (i.e. palpitations at rest after hard running). If I am faithfully repeating the doctor here, the papillary in my case just produces the PVC that set up my tachycardia, so I assume someone with out tachycardia could have just the PVC's.
Chest pain should be checked out by your doctor. You are young, have passed a prior stress test, and dont seem to have problems running, so it is unlikely you would have a blockage, but something else could be going on too. If you aren't already though, now would be a good time to start watching your diet.
For my own case, I had the sleep apnea, tachycardia, chest pain, severe anxiety, one episode of near syncope, gasping at night going on for a couple of months late last year, following a cold virus. All of these symptoms just ended one day. At some point during this process, I underwent 30 day heart monitor (captured string of posterior fascicular VT, which we are now saying is benign), and quite a bit later, a regular treadmill stress test which showed significant ST depression inidcating a blockage, a follow up echo stress test (which was normal - go figure), and cardiac MRI, which was normal. The VT was diagnosed as benign, and I have orders to continue running, and to notify the doctor if I experience problems with exercise. The day after my exam, I ran 6 miles with no issues, but there have been times when I have had questions about my exercise capacity : it just doesn't seem the same. Nevertheless, I have been operating with reduced calorie intake to shed some pounds, and when I upped my carbs, my sluggishness seemed to vanish.
In any case, the origin of my VT has been explained to me at left posterior papillary. The thought is that the papillary is stretched during hard exercise and become prone to PVC's. This creates an opportunity for re entrant, benign, tachycardia, which I have. I assume if you do not have that, you would just get a few PVC's. I did also come across a doctor that told me that the papillary is especially sensitive to blood flow issues because its supply is already limited, and that this could lead to some heart rhythm disturbances. It turns out that there are two normal variants in the way blood is distributed to these muscles. ST depression can be associated with right sided coronary blood flow, or with the left circumflex. This is an observation, not a diagnosis, but it is in the back of my mind since we are not going to just ignore the first stress test.
I also considered pericarditis since this followed a cold. Some of the symptoms were there. Unfortunately, the MRI and echo were performed after symptoms subsided. I also considered build up of catecholamines as a potential contributor to the VT. The doc says its caused by stretching in my case.
Hope this is helpful in some way. No doubt we are in different situations, and again I am not a doctor, just relating to you what I have been told.
Thanks so much for the advice. I will make an appointment today.
I would definitely head back to your cardiologist and this time ask for a 30 day monitor. This is a simple 2 lead device that you can wear continuously except for showering. I wore mine while running, skating, you name it...... The electrodes are replaced daily after showering and drying off. One goes over the just above the breast, and one on the intercostals. The recorder is a looping style, about the size of a deck of cards and will either auto record, and manually record. When it picks up an anomaly, it set up to jump back in time, and commit to a "memory slot" the time just prior to the event and for as much time after the event as the cardiologist sets up. If you're looking for PVCs, PACs, SVT, and such. you don't need to see all of the angles that a multi-lead recorder offers. Many of us here have experienced clusters of PVC's. When they become painful, I think you should seek consultation.
forgot to mention, my resting heart rate is in the low 40's.