In order to function normally, your body needs a blood pH of between 7.35 and 7.45. Alkalosis is when you have too much base in your blood, causing your blood pH to rise above 7.45. The lungs and the kidneys are the two main organs involved in maintaining a normal blood pH. The lungs do this by blowing off carbon dioxide, since most of the acid in the body is carbonic acid, which is made from carbon dioxide during metabolic processes. The amount of carbon dioxide removed is controlled by your breathing rate. The kidneys maintain blood pH by controlling the amount of bicarbonate, which is a base that is excreted from the body. The kidneys also control the amount of acids excreted from the body.
Respiratory alkalosis occurs when the lungs are blowing off more carbon dioxide than the body is producing. This usually occurs from hyperventilation. Your body's immediate response, after about 10 minutes of respiratory alkalosis, is a process called cell buffering. During cell buffering, hydrogen ions found in hemoglobin, proteins and phosphates, move out of the cells and into the extracellular fluid. There they combine with bicarbonate molecules and form carbonic acid. This process helps to reduce the amount of bicarbonate in the body and increase the amount of acid. However, while cell buffering occurs quickly, it does not have a huge effect on the body's pH. After about two to six hours of respiratory alkalosis the kidneys respond. They begin to limit the excretion of hydrogen and other acids and increase the excretion of bicarbonate. It usually takes the kidneys two or three days to reach a new steady state. In chronic respiratory alkalosis, the pH may constantly be high, but the body learns to adapt to it over time, with the help of the kidneys.