My heart rate is around 50 at rest. Does this mean I have it?
...yes, it can be seen on an x-ray.
Exertion as you describe on a regular basis without adverse effects (heart rate within parameters for age, etc.) can cause LV enlargement. It is not pathological (usually) and the heart pumps very efficiently. With this condition, the heart rate will/should be below 60 bpm at rest.