Heart Health and ultra sports?

silverharp

Trying to find out more about how particular activities could send you back up the "U curve" of exercise duration and health benefits. There are cardiologist who are reporting heart scarring and premature ageing in the hearts of endurance athletes. One cardiologist on a Ted talk summed it up along the lines of " run a marathon and then go and do something healthy"
Obviously a lot of factors, professional versus amateur versus recreational. In my own case I like cycling in the summer and try to build up 5ish hours including hills but I do cycle at a slow enough speed. So does the below piece square the circle where intensity might be the key factor and not absolute duration?

Curious on any thoughts?





http://www.menshealth.co.uk/fitness/adventure/The-everyman-guide-to-ultra-running

Myth: Extreme endurance running is bad for your heart

The most recent research on this subject, from the Swedish School of Sport and Health Sciences, found ultra-endurance competitors suffered no cardiac fatigue even after six days of non-stop exercise. Since the average work intensity of those monitored in the study was just 40%, this suggests it is exercise intensity, rather than exercise duration, which may cause heart damage.
Reap all the benefits of sustained cardio while dodging the potential pitfalls by breaking up a slow pace with periods of walking. “Introducing walking breaks makes a huge difference to your endurance and your perceptions of how far you can go,” says ultra running world-record holder William Sichel. Next time you head out for a long run, take a walking break of 5-10 minutes for every 30 minutes jogging. “Monitor how you feel at the end compared to your normal run,” says Sichel. “You will probably be amazed.”