Doctors, health organizations, and the U.S. surgeon general all agree that exercise is good for the heart. But the reasons why are not well understood. In a new study performed in mice, researchers from the Harvard Department of Stem Cell and Regenerative Biology, Massachusetts General Hospital, Harvard Medical School, and the Harvard Stem Cell Institute uncovered one explanation for why exercise might be beneficial: It stimulates the heart to make new muscle cells, both under normal conditions and after a heart attack.

Link to full Harvard Stem Cell Institute release.