Coordination of cardiac rhythmic output and circadian metabolic regulation in the heart

Over the course of a 24-h day, demand on the heart rises and falls with the sleep/wake cycles of the organism. Cardiac metabolism oscillates appropriately, with the relative contributions of major energy sources changing in a circadian fashion. The cardiac peripheral clock is hypothesized to drive many of these changes, yet the precise mechanisms linking the cardiac clock to metabolism remain a source of intense investigation. Here we summarize the current understanding of circadian alterations in cardiac metabolism and physiology, with an emphasis on novel findings from unbiased transcriptomic studies. Additionally, we describe progress in elucidating the links between the cardiac peripheral clock outputs and cardiac metabolism, as well as their implications for cardiac physiology.