The heart is made of cardiac muscle, consisting of special cells that are uniquely resistant to fatigue called cardiomyocytes.
Cardiomyocytes, the muscle cells of the heart, rely primarily on mitochondria as their power source. These mitochondria (the energy powerhouses of cells) exhibit a density that can be as much as 10x higher than that found in skeletal muscle cells. Cardiomyocytes are also better than ordinary muscle at extracting oxygen from the blood and are flexible in terms of fuel, able to consume glucose, free fatty acids and lactate.
This increased density of mitochondria and these 2 special abilities allow cardiomyocytes to generate and sustain energy output, which is crucial for the continuous contraction and pumping function of the heart and vital for supporting the high physical demands placed on your horse’s cardiovascular system during activities such as exercise or exertion.
The heart has evolved to perform its function brilliantly, tirelessly and incessantly – a good thing since rest days are not an option!