Synonyms for Keep Up (same or very similar meaning)
WordNet sense 1 (lengthen or extend in duration or space):
prolong, sustainWordNet sense 2 (keep in safety and protect from harm, decay, loss, or destruction):
conserve, maintain, preserve, conserveWordNet sense 3 (keep informed):
follow, keep abreastFrom the ODE community, based on WordNetadd/edit