P4423Extreme bradycardia in athletes is due to intrinsic changes within the heart

Abstract

Abstract Background It is well known that athletes and in particular endurance athletes have lower resting heart rates than non-athletes. This has generally been considered a healthy adaptation. Traditionally this was thought be due to increased vagal tone. Several studies have shown that endurance athletes continue to have lower heart rates in the absence of autonomic influence suggesting bradycardia is due to intrinsic changes within the heart. A subset of endurance athletes have very low heart rates with Tour de France cyclists having described heart rates in the 30s. It is unclear whether in these elite athletes with very low heart rate..