No chimpanzees or gorillas are in training for a fall marathon — a reflection, perhaps, of the ways in which the hearts of apes and men look and function as they do, according to a major new study of the health and evolution of cardiac muscles.

The study, which involved scanning the hearts of untamed primates and a wide variety of men, indicates that hearts adapt in telling ways to the needs of their owners. The findings likewise suggest that not getting enough of the right kind of exercise could mean that our hearts start to look just a little bit less human, and could impact our long-term health.

In general, mammalian hearts are quite malleable. They change in response to the demands placed on them. Recently, I wrote about a study showing that the hearts of elite swimmers and runners differ from one another slightly in shape and function and differ substantially from the hearts of those who aren’t athletes.

But until now, researchers had not examined whether and how this changing of the heart, known as its plasticity, might have played out during our evolution as a species and what that process could mean for our heart health today.