asthma vs labored breathing

asthma

noun
  • A long-term respiratory condition, in which the airways may unexpectedly and suddenly narrow, often in response to an allergen, cold air, exercise, or emotional stress. Symptoms include wheezing, shortness of breath, chest tightness, and coughing. 

labored breathing

noun
  • Breathing at less than 12 or more than 20 breaths per minute with poor or irregular quality, rhythm, or tidal volume; a sign of respiratory distress. 

How often have the words asthma and labored breathing occurred in a corpus of books? (source: Google Ngram Viewer )