A good working knowledge of normal human anatomy and physiology influencing breathing mechanics is required (Pryor and Prasad [230]). The sensation of breathlessness results from the multiple sensory inputs from chemical, mechanical and neural receptors that are interpreted in the central nervous system. This is a complex, multifaceted process. It may be influenced by, and impact on, bodily functions, activities and participation and environmental factors such as social support and financial resources. The physiological changes occurring as a result of deconditioning and inactivity are described in Section c27-sec-0267, Physical activity for people with cancer.