Elevation of the diaphragm occurs as pregnancy progresses. This is thought not to impair breathing ability because the rib cage flairs as a means of compensation.

Results:

The work of breathing is increased, both at rest and during exercise

The functional capacity of the lungs decreases about 25% by term due to decreases in lung reserve volume.

Results:

The work of breathing is increased both at rest and during exercise..

Hyperventilation occurs even during rest due to hormonal changes and changes at the respiratory control centers of the body.

Results:

Hyperventilation is exaggerated at all workloads.