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

BMJ 1998; 316 doi: (Published 13 June 1998) Cite this as: BMJ 1998;316:1784
  1. Jouko Karjalainen (, internista,
  2. Urho M Kujala, chief physicianb,
  3. Jaakko Kaprio, senior researcherc,
  4. Seppo Sarna, associate professorc,
  5. Matti Viitasalo, cardiologistd
  1. aCentral Military Hospital, Box 50, 00301 Helsinki, Finland
  2. bUnit for Sports and Exercise Medicine, Institute of Biomedicine, University of Helsinki, 00250 Helsinki
  3. cDepartment of Public Health, University of Helsinki, 00290 Helsinki
  4. dFirst Department of Medicine, Helsinki University Hospital, 00290 Helsinki
  1. Correspondence to: Dr J Karjalainen
  • Accepted 27 October 1997


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.

Subjects, methods, and results

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 …

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