How exercise grows a healthy heart

"Everyone knows that exercise comes with metabolic and cardiovascular benefits, but scientists understand surprisingly little about how physical activity influences the heart itself. Now, a new study in the December 23rd issue of Cell, a Cell Press publication, offers some of the first molecular-level insights. The studies in mice suggest that exercise turns on a genetic program that leads the heart to grow as heart muscle cells divide. It appears that shift in activity is driven in part by a single transcription factor (a gene that controls other genes). That gene, known as C/EBPb, was known to play important roles in other parts of the body, but this is the first evidence for its influence in the heart. "We've identified a pathway involved in beneficial cardiac hypertrophy – the good kind of heart growth," said Bruce Spiegelman of Harvard Medical School. The findings may have clinical implications, particularly for those with heart failure or other conditions that make exercise difficult to impossible, the researchers say. "This is yet another reason to keep on exercising," said Anthony Rosenzweig of Harvard Medical School. "In the longer term, by understanding the pathways that benefit the heart with exercise, we may be able to exploit those for patients who aren't able to exercise. If there were a way to modulate the same pathway in a beneficial way, it would open up new avenues for treatment." There may also be ways to optimize training regimens such that they tap into this natural mechanism more efficiently, Spiegelman added"