As we know that the preferred source of energy for our body (source) are carbohydrates but heart muscle is an exception and need some explanation for this exception, that why the preferred source of energy for or cardiac muscle are FATS?

  • $\begingroup$ What is the source of this claim? $\endgroup$
    – Chris
    Commented Apr 17, 2015 at 19:38
  • 3
    $\begingroup$ 1. ncbi.nlm.nih.gov/books/NBK22436 (point no. 2, last paragraph) 2. William's Basic Nutrition and Diet Therapy by Staci Nix , 13th edition. Chapter no. 2 Carbohydrates, page no 22. $\endgroup$ Commented Apr 17, 2015 at 19:54

1 Answer 1


Nice question! I've found a great article about fatty acid metabolism in heart muscle in healthy and disease conditions. As it is stated in this paper long chain fatty acids are utilized through beta-oxidation to meet the high energy need of continuous contraction. Beta-oxidation of long chain fatty acids produce far more ATPs than glucose. According to wikipedia:

For an even-numbered saturated fat (C2n), n - 1 oxidations are necessary, and the final process yields an additional acetyl CoA. In addition, two equivalents of ATP are lost during the activation of the fatty acid. Therefore, the total ATP yield can be stated as: (n - 1) * 14 + 10 - 2 = total ATP or 14n-6 (alternatively) For instance, the ATP yield of palmitate (C16, n = 8) is: (8 - 1) * 14 + 10 - 2 = 106 ATP

While a single molecule of glucose produces 36 ATPs (under aerobic conditions)

Thus use of fatty acids (fats) in cardiac muscle is beneficial because of their higher energy concentration. Also it is noteworthy that this does not occur in isolation, so this is a response to contractile work and other competing energy sources (such as glucose, lactose etc). Also excessive uptake and beta-oxidation in disease conditions can even endanger cardiac functions. See details in the linked paper.


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