Aims: 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. <p> Methods and Results: This prospective study included 20 484 adults (50.3% men) who participated in the third Tromsø Study survey in 1986-1987. At baseline, physical activity was assessed by a validated questionnaire, and ...