A normal healthy heart has the ability to choose its fuel from the menu of bioavailable substrates in the body. Glucose and fatty acids are the most common substrates, and the healthy heart switches seamlessly between the two depending on which is most available. For example, if you eat a candy bar, there is ample glucose in the blood, and the heart primarily uses that as its fuel source. In contrast, after going without food for some time, blood-sugar levels drop and the heart switches to fatty acids to provide its energy. The heart needs energy to contract, relax, repair, and rejuvenate itself. Continue reading “The hungry heart”