Cardiovascular Insufficiency develops when the need for blood flow and oxygen delivery exceeds the supply. This can develop with disease or with strenuous exercise. In the former there is a deficiency in the supply of blood and oxygen and in the latter the problem is the result of high demand. Often there is a mix of both limited supply and some measure of excessive demand. When demand exceeds supply, anaerobic metabolism will develop. Lactic acid is produced and begins to accumulate.
The total amount of lactic acid and lactate begins to rise and an acidemia develops. The process of metabolic acidosis from this anerobic metabolism leads to falling bicarbonate levels. Tissues that are highly metabolic, particularly muscle tissue contribute more to this than tissues with modest metabolic requirements such as internal organs. Some tissues such as bone will not suffer from this metabolic imbalance. Importantly the skin is not a highly metabolic tissue and will not suffer the relative lack of oxygen. For this reason cardiovascular insufficiency does not lead to cyanosis as respiratory illness does. A sensation of shortness of breath develops as a result of this cardiovascular insufficiency.