Actually l am pretty unfit now as it's been 5 years since l was able to do anything in a gym. I don't have an enlarged or athletic heart and just suspect that l always had a problem with Bradycardia, but as l was so active the specialists always put it down to that, and so didn't take me seriously. Now that l don't get below 49/50 l do feel better than l did. The max HR of 115 just seemed to stop me being able to dig deep and give my exercise that extra push, but l could still maintain constant fat burn and work up a sweat. Unfortunately for me l developed an aggressive prostate cancer in 2017 and after that everything ceased up and arthritis set in so now l am about as much use as a hand break on a canoe lol. Regards the arteries, the large ones are clear but the small ones are problematic and l have micro vascular angina which l get treatment for.