In a recently published study at Cedars-Sinai Heart Institute, stem cells obtained from younger subjects and injected into aging subjects resulted in improved heart function, and an overall increase in stamina and activity levels. As we age, our heart muscles begin to stiffen, causing fluid to build up in the heart and preventing the muscles from relaxing properly. This is similar to hearts of patients who have experienced heart failure with ejection fraction. Therefore, this research is pivotal in treating both heart failure and age-related deterioration. In an animal model, mice that received the progenitor cells (a more specified type of stem cell) obtained from younger mice showed multifaceted beneficial results. Not only did the older mice display improved heart function, but their activity levels increased, and their telomeres, which shorten as cells age, were regenerated. The implications of this research show that though the stem cells were injected into the heart, beneficial effects were seen all over the body, in addition to showing that younger stem cells are in fact far more proliferative than older cells.