Citric acid cycle

The citric acid cycle (CAC) also known as the TCA cycle (tricarboxcylic acid cycle) or the Krebs cycle is a series of enzyme-catalyzed chemical reactions that allow for aerobic respiration to occur within the mitochondria of the cell. When this cycle or its associated parts are not functioning properly subsequent fatigue may take place.

Citric acid cycle in ME/CFS
A 2016 paper started to define how and why people with ME/CFS might experience poorly functioning cellular respiration while a review of published papers added empirical evidence of a relationship between mitochondrial dysfunction and fatigue.

According to Ron Davis, speaking at the 2016 IACFS/ME conference, "ME/CFS patients have a marked decrease in some of the Citric Acid Cycle metabolites while mitochondrial mutations generally cause an increase."

Learn more

 * Wikipedia - Citric acid cycle
 * Krebs / citric acid cycle | Cellular respiration | tricarboxylic acid cycle| Biology | Khan Academy