Cardiorespiratory fitness and atrial fibrillation: A population-based follow-up study

Heart Rhythm. 2015 Jul;12(7):1424-30. doi: 10.1016/j.hrthm.2015.03.024. Epub 2015 Mar 14.


Background: Atrial fibrillation (AF) is the most common arrhythmia worldwide and has a complex association with physical fitness. The relationship of cardiorespiratory fitness (CRF) with the risk for AF has not been previously investigated in population-based studies.

Objective: The purpose of this study was to determine the relationship of CRF with incident AF.

Methods: CRF, as assessed by maximal oxygen uptake (VO2max) during exercise testing, was measured at baseline in 1950 middle-aged men (mean age 52.6 years, SD 5.1) from the Kuopio Ischaemic Heart Disease (KIHD) study.

Results: During average follow-up of 19.5 years, there were 305 incident AF cases (annual AF rate of 65.1/1000 person-years, 95% confidence interval [CI] 58.2-72.8). Overall, a nonlinear association was observed between CRF and incident AF. The rate of incident AF varied from 11.5 (95% CI 9.4-14.0) for the first quartile of CRF, to 9.1 (95% CI 7.4-11.2) for the second quartile, 5.7 (95% CI 4.4-7.4) for the third quartile, and 6.3 (95% CI 5.0-8.0) for the fourth quartile. Age-adjusted hazard ratio comparing top vs bottom fourth of usual CRF levels was 0.67 (95% CI 0.48-0.95), attenuated to 0.98 (95% CI 0.66-1.43) upon further adjustment for risk factors. These findings were comparable across age, body mass index, history of smoking, diabetes, and cardiovascular disease status at baseline.

Conclusion: Improved fitness as indicated by higher levels of CRF is protective of AF within a certain range, beyond which the risk of AF rises again. These findings warrant further replication.

Keywords: Atrial fibrillation; Cardiorespiratory fitness; Maximal oxygen uptake.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Atrial Fibrillation* / diagnosis
  • Atrial Fibrillation* / epidemiology
  • Atrial Fibrillation* / physiopathology
  • Exercise Test* / methods
  • Exercise Test* / statistics & numerical data
  • Finland / epidemiology
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Oxygen Consumption
  • Physical Fitness / physiology*
  • Proportional Hazards Models
  • Risk Factors
  • Statistics as Topic