wydechu

Wydechu is the Polish noun referring to the act or process of exhaling, i.e., expelling air from the lungs during respiration. In English the terms exhalation or expiration are commonly used. The word appears in medical and everyday Polish descriptions of breathing.

In human respiration, exhalation is the phase in which air leaves the lungs as the respiratory system returns to its resting volume. Quiet breathing is primarily passive, driven by the elastic recoil of the lungs and chest wall, aided by relaxation of the diaphragm and external intercostal muscles. During higher demand, such as exercise or vocalization, expiratory muscles contract to force air out more rapidly.

The flow of air is governed by pressure differences between the alveoli and the airways, and by airway resistance. Expiration involves volumes used in respiratory assessment: tidal volume is the air breathed in and out during normal breathing; expiratory reserve volume is the extra air that can be expelled after a normal exhalation; the total lung capacity includes these components along with inspiratory reserve and residual volume.

Exhaled air carries carbon dioxide produced by metabolism. Clinically, the exhaled gas is used in tests such as spirometry, which measures forced vital capacity and the rate of exhalation (FEV1), and in monitoring conditions with airway inflammation via fractional exhaled nitric oxide (FeNO).

Breathing techniques that emphasize controlled exhalation are used in medicine, singing, and relaxation practices. Diaphragmatic breathing promotes slower, deeper exhalations and can improve ventilation efficiency. In Polish medical terminology, wydechu denotes exhalation.