Exercise helps the heart to grow; a new Harvard study uncovers how

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Harvard Medical School has helped uncover some of the first molecular-level insights into how exercise benefits the heart.

The study in mice suggests that exercise activates a genetic program that prompts the heart to grow as heart-muscle cells divide.

A single transcription factor (a gene that controls other genes) known as C/EBPb had been shown to play vital roles in other parts of the body, but this study marks the first time its influence on the heart has been demonstrated.

Bruce Spiegelman of Harvard Medical School said researchers have identified the pathway involved in the "good kind of heart growth" known as beneficial cardiac hypertrophy.

With the finding, scientists may be able to exploit those same pathways for patients who aren't able to exercise, such as those with heart failure and other conditions that prevent them from exertion.

Heart muscle adapts to increased pressure and volume by increasing in size in response to exercise as well as hypertension. Those heart changes in hypertensive patients can result in heart failure and arrhythmias, however.

The new research allowed scientists to look at the difference between the "good kind" of heart growth and the kind that results from high blood pressure. The answer lies in transcription factor C/EPBb. Studies showed that a decrease in C/EPBb levels in mice leads to changes that appear to be consistent with those following exercise.

Mice with lower C/EPBb levels also were resistant to congestive heart failure.

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Review Date: 
December 28, 2010
Last Updated:
December 28, 2010