You can schedule when and how often to automatically build, rebuild, update, and purge an index by using the Catalog feature and a catalog batch PDX file (.bpdx). A BPDX file is a text file that contains a list of platform-dependent catalog index file paths and flags. You use a scheduling application, such as Windows Scheduler or Scheduler for Mac OS, to display the BPDX file in Acrobat. Acrobat then re-creates the index according to the flags in the BPDX file.
For more detailed information on scheduling an indexing update, search for BPDX on the Support page of the Adobe website.