Breathing is a normal vital function which is spontaneous, regular, self-regulating, quiet and effortless and reflects the way the respiratory system functions. The function of the respiratory system is to maintain the exchange of oxygen and carbon dioxide in the
lungs and tissues and regulate the acid-base balance. Any changes in this system will affect, and may present in the form of symptoms or signs in, other body systems. Breathlessness is a common symptom in people with cardiac diseases, respiratory diseases, neuromuscular disease, anaemia, significant gastro-oesophageal
reflux and can also be caused by pain, anxiety, emotion, deconditioning and obesity. Thorough, careful and systematic history-taking and assessment may help to identify the potential cause(s), with key question to identify whether the breathlessness is
acute (sudden onset) or chronic (long-standing).