Run at a comfortable pace, and not too far: James O'Keefe at TEDxUMKC - YouTube

Published on 27 Nov 2012

"The fitness patterns for conferring longevity and robust lifelong cardiovascular health are distinctly different from the patterns that develop peak performance and marathon/superhuman endurance. Extreme endurance training and racing can take a toll on your long-term cardiovascular health.  For the daily workout, it may be best to have more fun endure less suffering in order to attain ideal heart health."

Dr. James O'Keefe Jr. is the director of Preventative Cardiology Fellowship Program and the Director of Preventative Cardiology at Cardiovascular Consultants at the Saint Luke's Mid America Heart Institute, a large cardiology practice in Kansas City. He is the co-author of four bestselling books including The Forever Young Diet & Lifestyle (Andrews McMeel Publishing LLC, 2005). In 1989, he became a professor of medicine at the University of Missouri - Kansas City and has contributed to over 200 articles in medical literature. He is also the chief medical officer and founder of Cardiotabs, a company that creates nutritional supplements to aid in a healthy lifestyle.

Does Cardio Cause Heart Disease?

December 5, 2012 by Armi Legge 9 Comments

The United States has a big problem.

Heart disease is the number one cause of death, with one person dying every 39 seconds in the United States in 2008.⁽¹⁾

There is growing concern that too much cardio can damage your heart. This series will teach you if that’s true or not.

To help counter this problem, you’ve been told for years that one of the best ways to protect your heart is to exercise — especially “cardio” like swimming, cycling, and running.

There’s plenty of data to support that advice,^(2-4) but there’s also emerging evidence that too much cardio might damage your heart.

If this is true, it would mean that:

• Many of our best efforts to become healthier are really backfiring.
• Many of our favorite activities have been increasing our risk of an early death.
• As we watched athletes like Michael Phelps win 21 gold medals, we were also watching him damage his heart. 

Most of the information on this topic has been in the form of overhyped news articles focusing on single studies, misinterpretations of the research, pet theories, and anecdotes. You deserve a clear answer — an unbiased, thorough, critical examination of a simple question:

Does cardio damage your heart?

Whether you do cardio for the health benefits, enjoyment, or both, wouldn’t you like to know if your exercise regimen is secretly killing you?

How Cardio Might Damage Your Heart

In theory, excessive cardio causes small amounts of damage in the short-term. These small injuries turn into more significant long-term changes that can hurt your heart, blood vessels, and even kill you. This is thought to occur in a four step process:^(5-8)

1. Endurance exercise places a higher than normal load on your heart. It increases your oxygen and energy needs. It raises stress hormones, heart rate, blood pressure, and strains the walls of your heart. It also causes oxidative stress and inflammation. The heart is starved for oxygen and overwhelmed with these demands, and in some cases is irreversibly scarred by the exertion.
2. After each workout, your heart is tired from the effort and heart function drops. There are often changes in electrical activity, heart rate, and an increase in blood markers of heart damage. The inflammation and oxidative stress from the effort damages your heart, blood lipids, and blood vessels.
3. With enough training, your heart increases in size, develops erratic electrical activity, loses some of its ability to function, and develops small patches of scar tissue that grow with more training. The blood vessels around the heart and throughout other parts of the body also become harder and develop thicker deposits of calcium and plaque.
4. Over time, these long-term changes increase the risk of developing atherosclerosis, heart attack, coronary and peripheral artery disease, and in some cases, sudden cardiac arrest and early death.

 We’ll refer to this process as the “cardiotoxicity cycle.”

The Cardiotoxicity Cycle

Figure 1. The conceptual model of how cardio might cause heart disease.

Here is a good TEDx video from Dr. James O’Keefe. He is the author of several recent studies claiming that chronic endurance exercise is bad for the heart. It provides a nice summary of the cardiotoxicity cycle.