Which of the following is a common symptom of COPD?

Mr. Santos, a 65-year-old male, presents to the clinic with a history of chronic cough, sputum production and dyspnea on exertion. He has a long history of smoking and exposure to environmental pollutants. On physical examination, decreased breath sounds and prolonged expiration are noted. Spirometry results show a decreased FEV1 / FVC ratio. Mr. Santos is diagnosed with COPD.