Runners And Enlarged Heart How Can I Increase My Lung Capacity?

How can I increase my lung capacity? - runners and enlarged heart

I visited my doctor a few weeks ago and was surprised by my lung capacity. It is far below the average. It's really strange, because I can not hold my breath for 2 minutes. Ventrical left of me, my heart is enlarged and I am an endurance rider. I've never felt out of breath ... Can not breathe too long (less than average anyway).
What is the reason why I can not hold their breath longer than most people, but my lungs are so small? How do I get my lung capacity?
I am 5'11 "and 145 pounds for men.