End Stage (stage 4) of COPD means that FEV1 has less than 30 percent of normal predicted. You may often be short of breath, even at rest. You are often tired and short of breath and may have frequent exacerbations requiring extra treatment or even hospitalization. FEV1 is the forced expiratory volume in one second. The amount of air you blow out in the very first second, a key indicator of COPD.