Lung function refers to how well the lungs work to take in oxygen and expel carbon dioxide. It is measured through various tests that assess the volume of air the lungs can hold and how efficiently they can move air in and out. Key aspects of lung function include tidal volume, vital capacity, and forced expiratory volume. Healthy lung function is essential for overall well-being, as it supports the body's need for oxygen during activities like exercise and daily tasks. Factors such as smoking, air pollution, and respiratory diseases can negatively impact lung function, leading to breathing difficulties and reduced oxygen supply to the body.