Lung function refers to the ability of the respiratory system to perform ventilation, gas exchange, and regulation of oxygen and carbon dioxide in the body. In physiological anthropology, the study of lung functions is important for understanding how genetic, environmental, developmental, occupational, and lifestyle factors influence human adaptation and physical performance. Lung functions are commonly assessed through measures such as vital capacity, tidal volume, respiratory rate, forced vital capacity (FVC), and forced expiratory volume in one second (FEV₁). Age is an important factor affecting lung function. Lung capacity increases during childhood and adolescence as the lungs and thoracic cage develop. It generally reaches its maximum in early adulthood and gradually declines with advancing age due to reduced elasticity of lung tissue, weakening of respiratory muscles, and changes in the chest wall. Sex also influences pulmonary functions. On average, males have greater lung volumes than females of the same age and height, largely because of differences in body size, thoracic dimensions, and respiratory musculature. However, body composition and physical conditioning also contribute to these differences. Body size and stature have a strong relationship with lung capacity. Taller individuals generally possess larger lungs and greater vital capacity than shorter individuals. Thoracic dimensions, chest circumference, body weight, and body surface area can therefore influence respiratory measurements. Excessive obesity may reduce lung volumes