Described herein are compositions and methods related to use of cardiosphere-derived cells and their extracellular vesicles, such as exosomes and microvesicles, for achieving anti-aging and rejuvenation. This includes discoveries for effects on heart structure, function, gene expression, and systemic parameters. For animal studies, intra-cardiac injections of neonatal rat CDCs was compared to in old and young rats including evaluation of blood, echocardiographic, haemodynamic and treadmill stress tests. For in vitro studies, human heart progenitors from older donors, or cardiomyocytes from aged rats were exposed to human CDCs or cardiosphere derived cell (CDC) derived exosomes (CDC-XO) from pediatric donors. CDCs and CDC-XOs were capable of effectuating youthful patterns of gene expression in the hearts of old, along with a variant of physiological and function benefits, including elongation of telomere length. Together, these results indicate capacity of CDCs and CDC-XO to ward off the effects of aging through rejuvenation.