Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide. This condition is one of the four primary disturbances of acid–base homeostasis.

Respiratory compensation is also a condition where increased respiration reduces carbon dioxide sometimes to level below the normal range. In this case it is a physiological response to low pH from metabolic processes and not the primary disorder.

Signs and symptoms of respiratory alkalosis are as follows:

Respiratory alkalosis may be produced as a result of the following causes:

The mechanism of respiratory alkalosis generally occurs when some stimulus makes a person hyperventilate. The increased breathing produces increased alveolar respiration, expelling CO₂ from the circulation. This alters the dynamic chemical equilibrium of carbon dioxide in the circulatory system. Circulating hydrogen ions and bicarbonate are shifted through the carbonic acid (H₂CO₃) intermediate to make more CO₂ via the enzyme carbonic anhydrase according to the following reaction: ${\displaystyle {\rm {HCO_{3}^{-}+H^{+}\rightarrow H_{2}CO_{3}\rightarrow CO_{2}+H_{2}O}}}$

This causes decreased circulating hydrogen ion concentration, and increased pH (alkalosis).

The diagnosis of respiratory alkalosis is done via a test that measures the oxygen and carbon dioxide levels (in the blood), a chest x-ray, and a pulmonary function test of the individual.

The Davenport diagram is named after Horace W Davenport a teacher and physiologist which allows theoreticians and teachers to graphically describe acid base chemistry. It is not used by clinicians who prefer a practical rather than a theoretical approach