title: Elevated resting heart rate, physical fitness and all-cause mortality: a 16-year follow-up in the Copenhagen Male Study.
abstract: OBJECTIVE
  To examine whether elevated resting heart rate (RHR) is an independent risk factor for mortality or a mere marker of physical fitness (VO2Max).
  
  
  METHODS
  This was a prospective cohort study: the Copenhagen Male Study, a longitudinal study of healthy middle-aged employed men. Subjects with sinus rhythm and without known cardiovascular disease or diabetes were included. RHR was assessed from a resting ECG at study visit in 1985-1986. VO2Max was determined by the Åstrand bicycle ergometer test in 1970-1971. Subjects were classified into categories according to level of RHR. Associations with mortality were studied in multivariate Cox models adjusted for physical fitness, leisure-time physical activity and conventional cardiovascular risk factors.
  
  
  RESULTS
  2798 subjects were followed for 16 years. 1082 deaths occurred. RHR was inversely related to physical fitness (p < 0.001). Overall, increasing RHR was highly associated with mortality in a graded manner after adjusting for physical fitness, leisure-time physical activity and other cardiovascular risk factors. Compared to men with RHR ≤ 50, those with RHR > 90 had an HR (95% CI) of 3.06 (1.97 to 4.75). With RHR as a continuous variable, risk of mortality increased with 16% (10-22) per 10 beats per minute (bpm). There was a borderline interaction with smoking (p = 0.07); risk per 10 bpm increase in RHR was 20% (12-27) in smokers, and 14% (4-24) in non-smokers.
  
  
  CONCLUSIONS
  Elevated RHR is a risk factor for mortality independent of physical fitness, leisure-time physical activity and other major cardiovascular risk factors.
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, 2900 Hellerup, Denmark. magnustjensen@gmail.com
authors.forename: Magnus Thorsten
authors.initials: MT
authors.lastname: Jensen
authors.forename: Poul
authors.initials: P
authors.lastname: Suadicani
authors.forename: Hans Ole
authors.initials: HO
authors.lastname: Hein
authors.forename: Finn
authors.initials: F
authors.lastname: Gyntelberg
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000503:physiopathology; D002423:Cause of Death / Q000639:trends; D003718:Denmark / Q000453:epidemiology; D004562:Electrocardiography / Q000379:methods*; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012146:Rest / Q000502:physiology*; D012307:Risk Factors; D013997:Time Factors
keywords: Cardiac Function; Coronary Physiology