Tachypnea

Tachypnea or tachypnoea (Greek for "rapid breathing") is abnormally rapid breathing.

In adult humans at rest, any rate between 12 and 20 breaths per minute is normal and tachypnea is indicated by a ventilatory rate greater than 20 breaths per minute. Children have significantly higher resting ventilatory rates, which decline rapidly during the first three years of life and then steadily until around 18 years. Tachypnea can be an early medical sign of pneumonia in children.

Distinction from other breathing terms

Different sources produce different classifications for breathing terms.

Some describe tachypnea as any rapid breathing. Hyperventilation is then described as increased ventilation of the alveoli (which can occur through increased rate or depth of breathing, or both) where there is a smaller rise in metabolic carbon dioxide relative to this increase in ventilation. Hyperpnea, on the other hand, is defined as breathing more rapid and deep than breathing at rest.

Others give another classification: tachypnea is as any rapid breathing, hyperventilation is increased rate of breathing at rest, hyperpnea is an increase in breathing that is appropriately proportional to an increase in metabolic rate.