Exercise is a critical piece of my airway clearance. Vigorous walking, strenuous house or yard work, yoga or dancing provide great airway clearance as well as being fun or productive. Some members also run, jog, bike, or play tennis and other sports.

How much exercise depends entirely on the individual. It sounds like you are prone to hemoptysis (coughing up blood) so you need to be cautious. Maybe a course of pulmonary rehab could be helpful for you.

All that said, I think perhaps the brown sputum you saw after exercise was from deep in your lungs, and the activity helped your airway clearance. If the sputum is bright red it indicates a current bleed.