Scientists have always believed that the human heart stops producing new cells after birth and that these cells do not multiply but only grow in size as we age. However, according to a new study published in the “Journal of Physiology” exercise at an early age can increase the number of these cells and that these cells will remain with us for life. Scientists divided rodents into three groups. They started them on an exercise routine at ages that were equivalent to what humans would classify as childhood, adolescence and adulthood. All the groups had bigger cardiac-muscle cells but the childhood group had as many as 20 million additional cardiomyocytes (the type of cells that contract). The group that began as adolescents had some but fewer. Although exercise will benefit a heart at any age, these extra cells make it more likely to survive a heart attack in later years. Time to get the kids out there away from the TV, computer and video games and have them start adding those extra heart cells.