Left atrial enlargement in heart-- from training and cause for concern?

Hello. I went for my annual physical yesterday. I am happy to report that Clyde is as healthy as an ox, and the doctor was impressed with my HDL reading of 92. For the record I will be 49 years old next week.

In the EKG results that I just checked online, I saw the following notation (also during the appointment the doctor said the EKG was "fine", but did not mention the note below):

"Sinus Bradycardia -RSR(V1) -nondiagnostic. -Left atrial enlargement. BORDERLINE"


I checked on Dr. Google, and it appears that left atrial enlargement can be caused by heavy training. I plan to speak to my doctor about this today or tomorrow to see if it is cause for concern. I had a stress test last year and it came out great. I also figured I'd ask Dr. SS to get some thoughts here. I fear that the doctor will recommend that I take it easy, stop my training, and perhaps follow the government recommended training program that I read about here in a blog (sitting in a chair, rotating ankles, windmills with arms while sitting, etc.), rather than lifting heavy. Perhaps it is time to rotate ankles rather than doing heavy squats now that I am kicking 50.

Here is a paper I found. Any thoughts would be appreciated.

Atrial Enlargement in the Athlete's Heart - American College of Cardiology