title: Physical activity, resting heart rate, and atrial fibrillation: the Tromsø Study.
abstract: The objective was to examine the association of physical activity and resting heart rate (RHR) with hospital-diagnosed atrial fibrillation (AF) in a Norwegian cohort.
  
  
  
  This prospective study included 20 484 adults (50.3% men) who participated in the third Tromsø Study survey in 1986-87. At baseline, physical activity was assessed by a validated questionnaire, and RHR was objectively measured. Participants were followed from baseline through 2010 with respect to incident cases of hospital-diagnosed AF documented on an electrocardiogram. During a mean follow-up period of 20 years (409 045 person-years), 750 participants (70.5% men) were diagnosed with AF. Compared with the low physical activity group, moderately active individuals had a 19% lower risk of any AF [adjusted hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.68-0.97], whereas highly active had similar risk of AF. Vigorously active individuals showed a non-significantly higher risk of AF (adjusted HR 1.37, 95% CI 0.77-2.43). Risk of AF increased with decreasing RHR (adjusted HR 0.92, 95% CI 0.86-0.98 for each 10 b.p.m. increase in RHR), and RHR < 50 b.p.m. was a risk factor for AF (P < 0.05).
  
  
  
  In this prospective cohort study, leisure time physical activity was associated with AF in a J-shaped pattern. Moderate physical activity was associated with a reduced risk of AF, whereas higher activity levels attenuated the benefits of moderate activity. Low RHR was a risk factor for AF. Our results support the hypothesis that moderate and vigorous physical activity may affect AF risk via different pathophysiological mechanisms.
authors.affiliation: Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway School of Sport Sciences, UiT The Arctic University of Norway, 9037 Tromsø, Norway Centre for Clinical Research and Education, University Hospital of North Norway Trust, Tromsø, Norway bente.morseth@uit.no.
authors.forename: Bente
authors.initials: B
authors.lastname: Morseth
authors.affiliation: Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Sidsel
authors.initials: S
authors.lastname: Graff-Iversen
authors.affiliation: Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway.
authors.forename: Bjarne K
authors.initials: BK
authors.lastname: Jacobsen
authors.affiliation: Department of Health and Care Sciences, University of Tromsø, Tromsø, Norway Department of Clinical Therapeutic Services, University Hospital of Northern Norway, Tromsø, Norway.
authors.forename: Lone
authors.initials: L
authors.lastname: Jørgensen
authors.affiliation: Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway.
authors.forename: Audhild
authors.initials: A
authors.lastname: Nyrnes
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway Department of Community Medicine and Public Health, Institute of Medicine, Gothenburg University, Gothenburg, Sweden.
authors.forename: Dag S
authors.initials: DS
authors.lastname: Thelle
authors.affiliation: Department of Clinical Medicine, Aalborg University Hospital, Aalborg, Denmark Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Vestergaard
authors.affiliation: Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway Department of Cardiology, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Maja-Lisa
authors.initials: ML
authors.lastname: Løchen
mesh_terms: D001281:Atrial Fibrillation; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D015994:Incidence; D008297:Male; D009664:Norway; D011446:Prospective Studies; D012307:Risk Factors
keywords: Arrhythmia; Atrial fibrillation; Exercise; Physical activity; Resting heart rate