activity vs exercise

activity

noun
  • The state or quality of being active; activeness. 

  • The lexical aspect (aktionsart) of verbs or predicates that change over time and have no natural end point. 

  • Something done as an action or a movement. 

  • Something done for pleasure or entertainment, especially one involving movement or an excursion. 

  • The number of radioactive decays per unit time. Unit for it: becquerel or curie 

  • The propery of substances to react with other substances 

exercise

noun
  • A setting in action or practicing; employment in the proper mode of activity; exertion; application; use. 

  • Activity intended to improve physical, or sometimes mental, strength and fitness. 

  • The performance of an office, ceremony, or duty. 

  • Any activity designed to develop or hone a skill or ability. 

verb
  • To occupy the attention and effort of; to task; to tax, especially in a painful or vexatious manner; harass; to vex; to worry or make anxious. 

  • To use (a right, an option, etc.); to put into practice. 

  • To exert for the sake of training or improvement; to practice in order to develop. 

  • To perform physical activity for health or training. 

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