Is It a European Study of Atrial Fibrillation Among Cross-Country Skiers?

John Sutter: The thing that bothers me the most about this study is it was all men. There are very few women in Europe who are like big time endurance athletes, he says. "I wonder why they chose to do it that way," Sutter asks. 'What makes someone elite? We talking about a jog twice a week, three times a week, 50 miles a week'