prolong vs keep up

prolong and keep up both are verbs.

Word	Noun	Adjective	Verb	Adverb
prolong	No	No	Yes	No
keep up	No	No	Yes	No

As verbs, prolong and keep up are synonyms defined as:

Other synonyms of prolong include sustain.

prolong (verb)	keep up (verb)
lengthen in time; cause to be or last longer	prevent from going to bed at night
lengthen or extend in duration or space	keep informed
	maintain a required pace or level
	keep in safety and protect from harm, decay, loss, or destruction
	lengthen or extend in duration or space