Trying to understand the changes and their full implications is nearly impossible. 100 loc is a better top end imho.
https://www.goodreads.com/quotes/214064-if-you-owe-the-bank-...
When people start doing multiple things in a single commit with 1000's of changes, it does become mentally exhausting to review. Unfortunately, it requires either being extremely diligent when making the commits or being familiar with git rebase -i.
Of course, sometimes it's just thousands of lines of new code and impossible to review :).
this is why we have line printers, custom reading tables with balanced soft lighting (print proofing lamps) and more recently, rostrum cameras operated by foot switch.
review with fanfold might be a habit only acquired by formative experience, but once you physically manage the printout, and are comfortably seated with several hundred well spaced lines that aren't directly emitting typically exhausting spikey spectrum light forcing your brain to perform extremely complex colour management to balance your vision, which is the primary factor in concentration depletion in every attempt at testing we've tried over the years, and you mix in modern handwriting recognition and a pico projector display of feedback comments if necessary, I have only witnessed very high productivity. Anyone who is subject to audits will know the satisfaction of dumping fanfold boxes on the auditors desk. Or should.