Heart Muscle Renewed Over Lifetime, Study Finds

About 1 percent of the heart muscle cells are replaced every year at age 25, and that rate gradually falls to less than half a percent per year by age 75, concluded a team of researchers led by Dr. Jonas Frisen of the Karolinska Institute in Stockholm. The upshot is that about half of the heart’s muscle cells are exchanged in the course of a normal lifetime, the Swedish group calculates. Its results are to be published Friday in the journal Science.

“I think this will be one of the most important papers in cardiovascular medicine in years,” said Dr. Charles Murry, a heart researcher at the University of Washington in Seattle. “It helps settle a longstanding controversy about whether the human heart has any ability to regenerate itself.”