I work in an office and often feel short of breath and tired quickly, even without much physical activity. Are there any breathing exercises that can help improve lung function? (Minh Anh, 29, Hanoi)

Ms. Thi, 67, experienced severe coughing, shortness of breath, cyanosis, and vomiting, leading doctors to identify a 5 cm substernal goiter that had descended into her mediastinum, severely narrowing her airway.

I often feel short of breath and have chest tightness in hot weather, especially when outdoors or exercising. Is this a sign of lung disease? (Minh Tuan, Hanoi)

A 54-year-old man, who smoked a pack of cigarettes daily for 35 years, experienced sudden cardiac and respiratory arrest following 30 minutes of intense chest pain.