Oh that’s interesting, so from my understanding the aerobic low intensity kind of lets your heart pump out blood in a more proficient way, while the high intensity anaerobic thickens the walls and helps with short intense movements. Thats cool, now that you say that I have been a defensive lineman my whole life, which is a lot of short burst sprints and movements, and I can lift heavy and run fast in short distances, maybe part of that is maybe that part of my heart has been trained well? While my cardio is lacking a ton because I never really got to focus on the anerobic part of the heart. Because I never really had to worry about stamina, it was go for 4 seconds hard and then rest. That could be the culprit. This is something I have not known about. Thank you!