Fascinating article for all endurance athletes,& those of us who continue to push ourselves

[peacebird]

http://velonews.competitor.com/cycling-extremes

Here's just a snippet...

As for electrical abnormalities, the data speaks for itself. Long-term endurance exercise results in a five-fold increase in the risk of developing AF. A review of the relevant research finds many small studies that correlate long-term sports activity with AF (incidentally, Robert Gesink of Lotto-JumboNL had surgery in May 2014 for atrial fibrillation and has returned to the sport). Though none is conclusive, collectively they indicate a pattern: “Younger patients with a lower cumulative dose of exercise have lower AF risk. Older patients with higher dosages of exercise have higher AF risk,” Mandrola said.

“[People] criticize the studies that have been done that make this association. And they have a point: Each of the studies, individually, has flaws. They’re from one center, they include small numbers of athletes, and there’s selection bias. But taken together — there’s maybe ten to 20 single-center studies that show this association. If you put all that evidence together, there’s reason to believe that endurance athletes can develop AF.”

Perhaps the most influential study on mechanisms of AF in athletes comes from the study of rats and the effects of endurance exercise on the atria, conducted by a group of Spanish researchers and published in the journal Circulation in 2010. Rats were run one hour per day, five days a week, for up to 16 weeks. And they paid. Compared with sedentary controls, the exercised rats displayed evidence of damage, things such as enhanced vagal tone, atrial dilation, atrial fibrosis, and vulnerability to pacing-induced AF. Detraining the rats quickly led to a reduction in the vulnerability of AF, but not structural changes. Fibrosis and left atrial dilation remained after the rats stopped exercising. Is this what is happening inside your chest when you repeatedly go out and ride your bike, before work, after work, and every weekend in the summer?

[TexasProgresive]

1. So I have to maintain a razor edge balance

Between good sugar control or blowing up my heart.

[peacebird]

2. Seems counter intuitive but...