Physical activity, cardiorespiratory fitness, and cardiovascular outcomes in individuals with atrial fibrillation: the HUNT study.

AIMS: Atrial fibrillation (AF) confers higher risk of mortality and morbidity, but the long-term impact of physical activity (PA) and cardiorespiratory fitness (CRF) on outcomes in AF patients is unknown. We, therefore, examined the prospective associations of PA and estimated CRF (eCRF) with all-cause mortality, cardiovascular disease (CVD) mortality, morbidity and stroke in individuals with AF. METHODS AND RESULTS: We followed 1117 AF patients from the HUNT3 study in 2006-08 until first occurrence of the outcomes or end of follow-up in November 2015. We used Cox proportional hazard regression to examine the prospective associations of self-reported PA and eCRF with the outcomes. Atrial fibrillation patients meeting PA guidelines had lower risk of all-cause [hazard ratio (HR) 0.55, 95% confidence interval (CI) 0.41-0.75] and CVD mortality (HR 0.54, 95% CI 0.34-0.86) compared with inactive patients. The respective HRs for CVD morbidity and stroke were 0.78 (95% CI 0.58-1.04) and 0.70 (95% CI 0.42-1.15). Each 1-metabolic equivalent task (MET) higher eCRF was associated with a lower risk of all-cause (HR 0.88, 95% CI 0.81-0.95), CVD mortality (HR 0.85, 95% CI 0.76-0.95), and morbidity (HR 0.88, 95% CI 0.82-0.95). CONCLUSION: Higher PA and CRF are associated with lower long-term risk of CVD and all-cause mortality in individuals with AF. The findings support a role for regular PA and improved CRF in AF patients, in order to combat the elevated risk for mortality and morbidity.

Estimated Cardiorespiratory Fitness and Risk of Atrial Fibrillation: The Nord-Trøndelag Health Study.

PURPOSE: To investigate the association between estimated cardiorespiratory fitness (eCRF) and risk of atrial fibrillation (AF), and examine how long-term changes in eCRF affects the AF risk. METHODS: This prospective cohort study includes data of 39,844 men and women from the HUNT2 (August 15, 1995 to June 18, 1997) and the HUNT3 study (October 3, 2006 to June 25, 2008). The follow-up period was from HUNT3 until AF diagnosis or November 30, 2015. The AF diagnoses were retrieved from hospital registers and validated by medical doctors. A nonexercise test based on age, waist circumference, resting heart rate and self-reported physical activity was used to estimate CRF. Cox regression was performed to assess the association between eCRF and AF. RESULTS: The mean age was 50.6 ± 14.6 yr for men and 50.2 ± 15.2 yr for women. Mean follow-up time was 8.1 yr. One thousand fifty-seven cases of AF were documented. For men, the highest risk reduction of AF was 31% in the fourth quintile of eCRF when compared with the first quintile (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.53-0.89). For women, the highest risk reduction was 47% in the fifth quintile when compared with the first quintile (HR, 0.53; 95% CI, 0.38-0.74). One metabolic equivalent increase in eCRF over a 10-yr period was associated with 7% lower risk of AF (HR, 0.93; 95% CI, 0.86-1.00). Participants with improved eCRF had 44% lower AF risk compared with those with decreased eCRF (HR, 0.56; 95% CI, 0.36-0.87). CONCLUSIONS: The eCRF was inversely associated with AF, and participants with improved eCRF over a 10-yr period had less risk of AF. These findings support the hypothesis that fitness may prevent AF.

Physical activity modifies the risk of atrial fibrillation in obese individuals: The HUNT3 study.

Background Atrial fibrillation is the most common heart rhythm disorder, and high body mass index is a well-established risk factor for atrial fibrillation. The objective of this study was to examine the associations of physical activity and body mass index and risk of atrial fibrillation, and the modifying role of physical activity on the association between body mass index and atrial fibrillation. Design The design was a prospective cohort study. Methods This study followed 43,602 men and women from the HUNT3 study in 2006-2008 until first atrial fibrillation diagnosis or end of follow-up in 2015. Atrial fibrillation diagnoses were collected from hospital registers and validated by medical doctors. Cox proportional hazard regression analysis was performed to assess the association between physical activity, body mass index and atrial fibrillation. Results During a mean follow-up of 8.1 years (352,770 person-years), 1459 cases of atrial fibrillation were detected (4.1 events per 1000 person-years). Increasing levels of physical activity were associated with gradually lower risk of atrial fibrillation ( p trend 0.069). Overweight and obesity were associated with an 18% (hazard ratio 1.18, 95% confidence interval 1.03-1.35) and 59% (hazard ratio 1.59, 95% confidence interval 1.37-1.84) increased risk of atrial fibrillation, respectively. High levels of physical activity attenuated some of the higher atrial fibrillation risk in obese individuals (hazard ratio 1.53, 95% confidence interval 1.03-2.28 in active and 1.96, 95% confidence interval 1.44-2.67 in inactive) compared to normal weight active individuals. Conclusion Overweight and obesity were associated with increased risk of atrial fibrillation. Physical activity offsets some, but not all, atrial fibrillation risk associated with obesity.