Increase one's skill, status, or responsibility through effort, as in He worked up to 30 sit-ups a day, or She worked up to bank manager. Also see work one's way. [Second half of 1600s]
Intensify gradually, as in The film worked up to a thrilling climax. [Second half of 1600s]
Develop or produce by effort, as in Swimming always works up an appetite. [Second half of 1600s]