Lactic acid

Lactic acid is a metabolic byproduct produced during intense exercise, anaerobic respiration, and certain pathological conditions. It has a stimulatory effect on the production of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) 1.

The cell producing lactic acid is actually more alkaline than normal cells, despite the acidic nature of lactic acid itself. This is because the cell is producing lactic acid as a result of anaerobic respiration, which is a sign of cellular stress and a need for oxygen 2.

Lactic acid can have a negative impact on the body's ability to extract oxygen from the blood, leading to a hypoxic environment. In this state, the body's tissues cannot properly extract oxygen, and the lactic acid is shuttled to the liver for conversion back to glucose through the Cori cycle 3.

High levels of lactic acid can lead to lactic acidosis, a condition with a 20-30% mortality rate. This condition is often seen in patients with diabetic ketoacidosis, which coincides with lactic acidosis 3.

Lactic acid has opposing effects to carbon dioxide, which can help to alleviate lactic acidosis. Studies have shown that giving carbon dioxide can turn off lactic acid production and alleviate metabolic acidosis 6.

The production of lactic acid can also have a negative impact on the body's ability to breathe, leading to an increased impulse to breathe and a vicious circle of lactic acid production and increased adrenergic response 7.

In certain environments, such as high altitude, the body's production of lactic acid can be reduced, leading to a decrease in blood oxygen affinity and an increase in oxygen availability to the tissues 4.

The metabolism of lactic acid can also have a negative impact on the body's ability to produce collagen and other structural proteins, leading to a decrease in the body's ability to repair and renew tissues 8.