bear down vs break a sweat

bear down

verb
  • To intensify one's efforts. 

  • To approach in a determined manner. 

  • To steer away from the wind; to approach from windward. 

  • To exert downward pressure on one's abdomen, as in giving birth, forcing out feces, and some similar bodily maneuvers. 

  • To push (someone) to the ground; to defeat, overcome. 

  • Used other than figuratively or idiomatically: see bear, down. 

break a sweat

verb
  • To put effort into something. 

  • To start sweating. 

How often have the words bear down and break a sweat occurred in a corpus of books? (source: Google Ngram Viewer )