Editing a lengthy word doc with track changes on a Mac

I'm working on an 85k Word Doc on a Mac with numerous track changes, comments, replies, etc. I am experiencing regular slow downs and I'm getting the spinning 'beachball' far too often. I have two questions:

1. Is the solution to break the 85k doc into two or three sections?

2. Was it even realistic for me to be trying to edit/track changes/comments/replies/etc on one 85k doc in the first place?