An attenuated heart rate recovery immediately after exercise, thought to be a marker of reduced parasympathetic activity, has been demonstrated to be an independent predictor of all-cause mortality in several large-scale studies; however, the mechanisms by which impaired heart rate recovery confers an increased risk of death are not clear. From clinical observation, vagal reactivation was thought to be the major determinant of the decrease in heart rate during the first 30 seconds of recovery, independent of age and the intensity of exercise; however, patients with attenuated heart rate recovery were also shown to have lower exercise workload, shorter exercise duration, lower numbers achieving 90% target heart rate, and even impaired endothelial function. This review focuses on the roles of heart rate recovery and endothelial function in predicting future mortality and their interaction.