Acidosis (hyperacidity) refers to an acidic pH value of the blood. The normal pH of the blood fluctuates only very slightly between pH 7.36 and 7.44. The blood has a number of different buffer systems that ensure that the pH stays within these limits, regardless of whether we ingest acids or bases through our food, for example, or whether we produce a lot of lactic acid (lactate, an acid produced by anaerobic glycolysis) as a result of physical exertion such as endurance running. Roughly speaking, the acid-base balance is mainly influenced by two major systems: respiration and our metabolism. Disturbances in one of these two systems can lead to acidosis.

Functionality of the acid-base balance

A “normal” pH value in our blood is very important because all our metabolic processes work best in this area. If acidosis develops, the metabolic processes cannot function properly. Two major systems influence our acid-base balance: respiration and metabolism.

Respiration is influenced by the carbon dioxide (CO2) actuator: if we breathe deeper and faster, we exhale more carbon dioxide. Carbon dioxide reacts in our blood as acid (through a reaction with water to form carbonic acid). This means in simple terms: the more and the deeper we breathe, the less acid is in our blood and vice versa: If we breathe shallowly or shallowly, more acid remains in our body and acidosis develops.

The second control element is the metabolism. With a normal diet, we consume more acids than bases every day. In order to maintain our fixed pH value, we therefore have to excrete acids in our urine. If this is disturbed we get acidosis. Our body also produces acids (such as lactic acid) during great physical exertion and in the event of oxygen deficiency.


Acidosis can cause a variety of different symptoms. While a slowly developing acidosis is often accompanied by little to no symptoms, an acute acidosis shows pronounced symptoms. These can be disturbances of consciousness with fatigue, headaches, memory disorders and changes in personality up to unconsciousness (acidotic coma).

There may also be coordination disorders and trembling of the hands. In mild acidosis, muscle weakness may also be the main symptom. Low acidosis often leads to high blood pressure, while high acidosis is more likely to be accompanied by a drop in blood pressure.

In addition, cardiac arrhythmia with slow heartbeat and heart stumbling (arrhythmias) can follow. Intestinal activity is reduced and constipation and abdominal pain may occur. In addition to these general symptoms, various other symptoms can also occur, depending on the cause of the acidosis.

If the disturbance is caused by an obstruction of breathing (as in the case of lung disease, for example), a particularly rapid impairment of consciousness can follow with the maximum form of coma (“CO2 narcosis”). In case of longer habituation due to chronic lung diseases, general symptoms such as fatigue, headaches, muscle weakness and hand trembling are more likely to be in the foreground. If the acidosis has its cause in the metabolism, further symptoms occur in addition to the above-mentioned symptoms, which are caused by a counter regulation of breathing.

In order to get rid of the additional acids from the body, those affected breathe more deeply. This results in regular, particularly deep breathing, the so-called kissing mouth breathing. In some cases this breathing can normalize the pH value of the blood.