Warning: If You Do This Type of Exercise, You Could Be Damaging Your Heart

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There exists a general consensus that exercise is good for you. To an extent, this is very true. However, what most people fail to realize is that, like everything else, too much exercise is unhealthy – and the damaging effects of extreme endurance exercise has been supported by numerous scientific studies – ten of which we list below.

But how can an activity that is being recommended by healthcare professionals be bad for you? Just how does excessive exercise affect our body? It really depends on how much you do – and extreme endurance exercise is now considered potentially dangerous.

The Good Side Of Exercise
Exercising regularly has many benefits. Moderate exercise activity at least three times a week for thirty minutes to an hour each is enough to:

• Improve your endurance
• Strengthen your muscles (including your heart!)
• Deliver more oxygen to the rest of the body
• Help you maintain a healthy weight
• Improve your mood through endorphin production (endorphins are happy hormones!)

These benefits are excellent reasons to keep exercising regularly. The major problem with over-exercising, however, is that the body remains in a post-workout state, not allowing the body enough time to rest and repair for the next bout of exercise. We constantly strain our body – especially our heart. This can cause rapid burnout and – in the worst case scenario – even a heart attack.

The Bad Side Of Exercise
Recent studies in the past ten years have discovered how too much exercise does more harm than good. High-endurance activities like marathons and triathlons can:

• Overwork the heart and cause cardiac dysfunction
• Damage muscle fibers
• Elevate cortisol levels in the body, a stress hormone
• Cause excessive fatigue
• Increase injury risk

How do we know how much is too much? How much exercise does a person have to do for it to be considered unhealthy and damaging? These scientific reports give some useful information:

Ten scientific studies that have discovered negative effects of too much exercise

#1: Durand & Gutterman (2014) studied the vascular function of conditioned athletes and found similarities with people affected with coronary artery disease. This suggests that the way over-exercising stresses our heart and blood vessels are likened to cardiac dysfunction and disease. ^[1]

#2: According to Lavie, O’Keefe, & Salis (2015), high doses of physical activity and exercise can cause cardiac arrhythmias, heart disease, and dysfunction, and release of troponin and brain natriuretic peptides, chemical markers of heart damage. ^[2]

#3: Two of previously mentioned researchers, Lavie and O’Keefe, along with Guazzi (2015) applied statistics in looking at potential dangers of extreme endurance exercise among school-age athletes. They hypothesized if a dose-response curve is applicable to therapeutic exercise, there must be an upper limit until exercise becomes dangerous. ^[3]

#4: In heart attack survivors, it was discovered that while general exercise lowered mortality risk, higher levels of exercise (running more than 7.1 km/day or walking more than 10.2km/day) increased the risk of mortality as much as three-fold. ^[4]

#5: According to one recent study (2012), too much exercise permanently changes the vasculature of the blood vessels and the heart itself, overloads the atria and ventricles, stiffens their walls, and contributes to coronary artery calcification, among a list of cardiac dysfunctions. ^[5]

#6: Heatstroke is a common condition experienced by endurance athletes. In a 2008 study on more than 28,000 endurance cyclists, five of whom died after long races, it was discovered that excessive endurance exercise contributed significantly to high internal temperatures (endothermy), causing heatstroke and death. ^[6]

#7: A 2012 study found out that participating in long-term endurance sports places a high strain on the right ventricle, causing ventricular cardiomyopathy, and making it prone to ventricular arrhythmias. This can lead to cardiac arrest. ^[7]

#8: In an article published by the Oxford University Press, two studies were highlighted that showed how athletes developed cardiac abnormalities after long-term endurance exercise. The studies revealed how older endurance athletes developed myocardiac fibrosis, or the thickening of the cardiac muscle, and scarring of the heart tissue. ^[8]

#9: In a study published by the New England Journal of Medicine, researchers concluded that marathons and half-marathons reduced the risk for cardiac arrest, but male endurance athletes were still more likely to experience heart attacks and cardiac dysfunction compared to other population groups. ^[9]

#10: The American Heart Association studied several cases involving endurance athletes and cardiovascular problems and concluded that “endurance exercise most likely increases your chances of living longer but may increase your risk of some arrhythmias”. This sentence is full of uncertainty but it implies that further research is needed to make a solid conclusion on endurance exercise and how it affects the heart. ^[10]

Conclusion: Like so many other things, moderation is key