WHY DO CARDIOMYOCYTES (HEART MUSCLE CELLS) STORE GLYCOGEN?
A cardiomyocyte, deprived of its blood supply, cannot continue beating for more than a few minutes at the very most. The glycogen would therefore only be useful to survive a 40-60 second angina attack at the very most. Since ischaemic heart disease hardly ever occurs before the age of 50 years, and would have been an extreme rarity in past centuries, and during our long evolutionary history on the African savannah, it hardly seems likely that natural selection would have included a precautionary feature such as this into our physiologies from childhood. This question is possibly related to other metabolic conundrums involving carbohydrate metabolism. Why, for instance, do we need a constant supply of glucose, when we could, supposedly, obtain all our energy from burning fats? Or, why does a glycogen depleted skeletal muscle become effectively paralysed (i.e. unable to exercise) when its blood supply is not compromised, and its supply of oxygen and fatty acids could still presumably sup
