Final answer:
Difficulty breathing is known as dyspnea, a common symptom in conditions such as COPD and sleep apnea, and can be evaluated using diagnostic tools like spirometry.
Step-by-step explanation:
Difficulty breathing is known as dyspnea. This term is used to describe a subjective sensation of uncomfortable, labored, or difficult breathing which a person may experience. In the context of different conditions affecting the respiratory system, such as Chronic Obstructive Pulmonary Disease (COPD) or different forms of sleep apnea, dyspnea is a common symptom. In the case of COPD, patients may experience persistent respiratory difficulties and coughing with sputum production. With sleep apnea, breathing interruption occurs due to improper respiratory center responses in the brain, or obstruction in the respiratory tract. Spirometry is a diagnostic tool that measures the volume of air a patient can exhale and is useful in diagnosing respiratory diseases.