The function of the Cardiovascular System is to circulate blood.
When the circulation of blood is insufficient to meet demand the term Cardiovascular Insufficiency is appropriate. This is demonstrated when oxygen delivery is limited and anaerobic metabolism develops.
This term is appropriate even in athletes or healthy individuals that exercise vigorously enough to develop an oxygen debt. This is a natural process in all mammals and does not represent illness. In this case the flow of blood is supra-normal but the supply does not meet demand because of very high demand. The term Cardiovascular Insufficiency in this does not imply disease. This is in distinction to the term or diagnosis of Heart Failure or Acute Heart Failure which is then a disease state.
Often there is a mix of both limited supply and some measure of excessive demand. When demand exceeds supply for whatever reason, anaerobic metabolism will develop.
When Cardiovascular Insufficiency develops lactic acid is produced and begins to accumulate. This happens in health and disease. The total amount of lactic acid begins to rise and an acidemia develops. The process of metabolic acidosis from this anaerobic 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 when flow is normal or supranormal. 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. This is notably seen in runners after a race particularly the “middle distance” races like 800 meters or 1600 meters.