Lone atrial fibrillation in vigorously exercising middle aged men: case-control study

Regular physical exercise reduces cardiovascular morbidity.1 2 However, our clinical impression is that atrial fibrillation is quite common in otherwise healthy middle aged men engaged in long term vigorous endurance sports. We therefore compared the prevalence of atrial fibrillation in middle aged men doing intense endurance training and men from the general population. We chose top level veteran orienteers to represent subjects doing long term vigorous exercise. A high position in the veteran ranking list is an indicator of years of intense training. We enrolled the 60 top ranked orienteers in 1984 from the race classes age 35-39 years, 40-44 years, 45-49 years, and 55-59 years, a total of 300 runners. The 495 controls comprised all men aged 35-59 enrolled for an earlier study.2 At 20 years old these subjects had been completely healthy (fully fit for military …