Exhalation

Exhalation (or expiration) is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing.

Exhaled air is rich in carbon dioxide, a waste product of cellular respiration during the production of energy, which is stored in ATP.

Exhalation has a complementary relationship to inhalation; the cycling between these two efforts define respiration.

During forced exhalation, as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles, generate abdominal and thoracic pressure, which forces air out of the lungs.

It is during exhalation that the olfaction contribution to flavor occurs in contrast to that of ordinary smell which occurs during the inhalation phase