These changes in lung function are caused by fat accumulation in the chest wall and abdominal cavity, compressing the thoracic cage, diaphragm, and lungs, consequently causing a decrease in diaphragm displacement, adecrease in lung and chest wall compliance
, and an increase in elastic recoil, resulting in a decrease in lung volumes, and an overload on inspiratory muscles, impairing ventilatory function.
"Abdominal obesity may mechanically affect the diaphragm and chest wall compliance
with decreased lung volumes."
 Increased IAP may affect the viscoelastic properties of the thoraco-abdominal region, elevating chest wall resistance, decreasing chest wall compliance
and inducing pulmonary oedema.
Since it is essential for CF patients to maintain and improve mobility of the chest wall, abdominal and thoracic dimensions and kinematics measurements were used as an evaluative method for diaphragmatic breathing excursion to quantify possible alterations in thoracic capacity and abdominal and chest wall compliance
as achieved by all expiratory and inspiratory muscles.13 By measuring the abdomen and thorax with a nondistendable measuring tape in centimetres to the nearest 0.1 cm during rest, maximal inspiration and expiration over the second intercostal space, xiphoid process and mid-point between the xiphoid process and umbilicus, a competency in diaphragmatic breathing can be demonstrated by a reduction in rib cage excursion.
Adjusting tidal volume to stress index in an open lung condition optimizes ventilation and prevents overdistension in an experimental model of lung injury and reduced chest wall compliance
. Crit Care 2015;19:9.
 Female subjects tend to have lower PFT values as their respiratory muscle endurance and chest wall compliance
is lower than that of their male counterparts.
Increased chest wall compliance
impedes the oxygenation of the healthy dependent lung unlike adults.
Because of the excess chest wall weight with subsequent reduced chest wall compliance
, ventilation is even more difficult in obese patients.
The change in PPV and SVV during pneumoperitoneum might be attributable to a decrease in chest wall compliance
caused by an increase in abdominal pressure (22).
An important difference between children and adults with regard to blunt chest injury is that children have greater chest wall compliance
than adults due to greater cartilage content and incomplete ossification of the ribs.
He outlines the history of respiratory physiology and the structure and function of the thoracic region, then preparation, basic spirometry, and measures for airway responsiveness and resistance, lung volume, single-breath, lung, chest wall compliance
, and maximal pressures, blood gasses and pH, and exercise, as well as ethnic differences, final interpretation, and quality control and normal laboratory variability, with 10 cases.
Obesity is found to decrease the lung volume and capacities by decreasing both lung and chest wall compliance
.  There is also an increase in resistance to outflow of air through the airways in the obesity.