energize vs overburden

energize

verb
  • To invigorate; to make energetic. 

  • To supply with energy, especially electricity; to turn on power to (something). 

overburden

noun
  • A sterile stratum that lies above the stratum being investigated 

  • The rock and subsoil that lies above a mineral deposit such as a coal seam. 

verb
  • To overload or overtax. 

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