COPD is an umbrella term that includes both chronic bronchitis. Patients with emphysema experience shortness of breath due to a reduction in the elasticity and eventual damage to the air sac walls in the lungs. This leads to impaired exhalation and a resultant build-up of carbon dioxide in the lungs. These patients typically present as underweight, often exhibiting significant weight loss due to the increased energy output associated with laboured breathing (Wouters, 2000)