This chapter highlights the hallmarks of cardiac aging, distinguishing characteristics between cardiac aging and cardiac senescence. An overview of the molecular mechanisms underlying cardiac aging, with a particular focus on the role of reversible protein acetylation, emphasizes the role of sirtuins in regulating heart function and structure. The chapter explores how alterations in energy metabolism contribute to heart dysfunction, with a focus on the impact of mitochondrial dysfunction and phenomena of protein acetylation, along with the role of acetylase and deacetylase in an aging heart. Additionally, the chapter discusses the regulation of cardiomyocyte proliferation and the potential for enhancing cardiac regeneration. Finally, therapeutic strategies, including caloric restriction and HDAC inhibitors, microRNAs, stem cells, and other pharmacological agents are examined as potential approaches to slow or reverse the effects of cardiac aging.