NOV 28, 2015 8:56 AM PST

When Exercise Does More Harm Than Good

WRITTEN BY: Kara Marker
Normally exercise is viewed as a healthy activity that keeps us fit and our body functioning efficiently. However, in people with a certain genetic mutation, intense exercise can actually lead to early development of a severe heart condition.

Arrythmogenic ventricular cardiomyopathy (AVC) is a heart condition exacerbated by exercise and is the most common cause of cardiac death during exercise. Findings from a recent study published in American Journal of Physiology - Heart and Circulatory Physiology looked at mice with certain gene mutations that negatively impacted the strength of their heart walls in cases of AVC. 

The heart wall is made up of interconnected and overlapping heart cells connected by desmosomes. Proteins like desmoplakin are combined to make desmosomes, and when the mice had desmoplakin protein mutations, the heart wall structure faltered and was more prone to damage. 

Scientists were able to connect desmoplakin mutations to cases of AVC, for when heart cells detach after being overstretched during extensive exercise, the imperfect desmosomes are unable to maintain the integrity of the cell walls. Scar tissue grows in between overstretched heart cells, further inhibiting the heart wall ability to withstand stretching during exercise. 

By making the connection between desmoplakin mutations and AVC, scientists hope to develop a strategy for individuals who already have the condition and want to exercise. In addition, scientists can potentially pinpoint which patients are at risk for developing early onset AVC. 

In addition to a weakening of the heart cell wall in mouse AVC models, mice with desmoplakin mutations also altered the signaling of the Wnt-Beta-catenin pathway, which promotes new cell growth and prevention of fat deposition in healthy hearts. 

In the future, the scientists involved in this study aim to detect changes in heart cell links before serious AVC symptoms occur. In addition, they plan to develop better strategies to prevent AVC complications and potentially medications targeting the Wnt-Beta-catenin pathway.

Watch the video below to hear about an individual case of AVC.

Source: American Physiological Society
About the Author
I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
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