How does IMT help with overall cardiorespiratory efficiency?

The heart and lungs are interdependent, which is the basis of cardiorespiratory fitness. This includes Ventilation/Perfusion (V/Q) relationships within the lungs and throughout the body. Without blood supply or O2 delivery, things do not function at the most basic level. Cardiac benefit is likely realized by increased venous return (blood flow back to the heart), stronger heart muscle, and more cardiorespiratory efficiency.