Memory consolidation happens largely during sleep. What you read exists first as a fragile trace, and it is during sleep - particularly deep and REM stages - that it is stabilised into something you can retrieve under pressure. This is one of the more solidly established findings in memory science, replicated in laboratories for decades. Reading for sixteen hours and sleeping for three stores less than reading for ten and sleeping for seven. Studying without sleeping is pouring water into a bucket you have not repaired.

The practical consequences are specific. Front-load the hardest material into the earlier hours, when encoding is strongest, rather than saving it for 3am when you are merely moving your eyes across a page. Review the most difficult topic in the last thirty minutes before sleeping. And protect the night before the exam absolutely - sleep deprivation degrades working memory, reasoning speed and error-checking, which is a precise description of what an examination measures.

Then deal with the real constraint rather than pretending it does not exist. Night reading is often forced by noise, lectures, crowded hostels, and power that only behaves after midnight. If night truly is your only quiet window, shift your sleep rather than delete it - sleep from 10pm to 3am and study from 3am to 7am, consistently. Consistency matters nearly as much as duration, because an erratic schedule keeps your body permanently jet-lagged.