respiration vs shortness of breath

respiration

noun
  • The process of inhaling and exhaling; breathing, breath. 

  • Any similar process in an organism that lacks lungs that exchanges gases with its environment. 

  • An act of breathing; a breath. 

  • The process by which cells obtain chemical energy by the consumption of oxygen and the release of carbon dioxide. 

shortness of breath

noun
  • difficulty in breathing; dyspnea 

How often have the words respiration and shortness of breath occurred in a corpus of books? (source: Google Ngram Viewer )