Cardiac Risk of Extreme ExerciseSharalaya, Zarina, MD; Phelan, Dermot, MD, PhDSports Medicine and Arthroscopy Review: March 2019 - Volume 27 - Issue 1 - p e1–e7 doi: 10.1097/JSA.0000000000000215 Digital Exclusive Abstract Author InformationAuthors Article MetricsMetrics Habitual moderate intensity exercise is a vital component of a healthy lifestyle. For most of the population, increasing exercise duration and intensity beyond current recommendations appears to impart additional cardiovascular benefits; however, recent data has raised the possibility of an inflection point after which additional exercise no longer imparts benefit and may even result in negative cardiovascular outcomes. Exercise at the extremes of human endurance places a large hemodynamic stress on the heart and results in occasionally profound cardiac remodeling in order to accommodate the huge increases in cardiac output demanded by such endeavors. These changes have the potential to become maladaptive and heighten the risk of various arrhythmias, influence the rate of coronary atherosclerosis, and alter the risk of sudden cardiac death. Herein, we will discuss the potential negative impact of extreme exercise on cardiovascular risk. Department of Cardiovascular Medicine, Sports Cardiology Center, Cleveland Clinic, Cleveland, OH The authors declare no conflict of interest. Reprints: Dermot Phelan, MD, PhD, Desk J1-5, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.