Relation of whole blood n-3 fatty acid levels to exercise parameters in patients with stable coronary artery disease (from the heart and soul study)

Dietary intake of n-3 polyunsaturated fatty acids is associated with a lower incidence of cardiovascular events. Mechanisms underlying this association are poorly understood but may include beneficial effects on physical conditioning and vagal tone. We investigated the association of n-3 fatty acid levels to exercise parameters in 992 subjects with stable coronary artery disease. Cross-sectional associations of heart rate recovery time, treadmill exercise capacity, and exercise time with docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels were evaluated in multivariable linear and logistic regression models adjusted for demographics, cardiovascular risk factors, co-morbidities, self-reported physical activity, medication use, and left ventricular function. After multivariable adjustment, n-3 fatty acid levels (DHA + EPA) were strongly associated with heart rate recovery (beta 2.1, p = 0.003), exercise capacity (beta 0.8, p <0.0001), and exercise time (beta 0.9, p <0.0001). Increasing levels of (DHA + EPA) were also associated with decreased risk of impaired heart rate recovery (odds ratio 0.8, p = 0.004) and exercise time (odds ratio 0.7, p = 0.01) and trended toward significance for exercise capacity (odds ratio 0.8, p = 0.07). These associations were not modified by demographics, body mass index, smoking, co-morbid conditions, statin use, or β-blocker use (p for interaction >0.1 for all comparisons). In conclusion, an independent association exists between n-3 fatty acid levels and important exercise parameters in patients with stable coronary artery disease. These findings support the hypothesis that n-3 fatty acids may increase vagal tone and physical conditioning.