Dieting complex carbohydrates and fats, for energy. The first source to which the body turns is glycogen (by glycogenolysis). Glycogen is a complex carbohydrate, 65% of which is stored in skeletal muscles and the remainder in the liver (totaling about 2,000 kcal in the whole body). It is created from the excess of ingested macronutrients, mainly carbohydrates. When glycogen is nearly depleted, the body begins lipolysis, the mobilization and catabolism of fat stores for energy. In this process, fats, obtained from adipose tissue, or fat cells, are broken down into glycerol and fatty acids, which can be used to generate energy.
Equine exertional rhabdomyolysis cell membranes may then be damaged if the horse is forced to continue work, which allows muscle enzymes and myoglobin to leak into the bloodstream. The body builds up a store of glycogen from converted carbohydrates in muscle cells. Glycogen, a fuel used by muscles for energy, is depleted during work and restocked when a horse rests. Oxygen-carrying blood metabolizes glycogen, but the blood can not flow fast enough to metabolise the excess stored glycogen. The glycogen that is not metabolized aerobically (by the oxygenated blood) must then be metabolized anaerobically, which then creates the cell waste products and heat,