Students preparing for exams often sacrifice sleep, believing that extra hours of study will lead to better results. Research on sleep and memory suggests that this strategy may be counterproductive.

When we learn something new, the information is initially fragile. Sleep appears to play an important role in stabilising these new memories, a process scientists call consolidation. During deep sleep, the brain seems to replay recent experiences, strengthening the connections that represent them. Studies in which participants learn a list of words or a new skill, then either sleep or stay awake, have generally found better recall in those who slept.

Sleep before learning matters too. People who are sleep-deprived typically find it harder to concentrate and to take in new information, so a late night before a lecture can reduce how much is learned in the first place.

None of this means that sleep can replace study. Memories that were never properly formed cannot be consolidated. However, it does suggest a more effective routine: spreading study over several days, testing yourself rather than simply rereading notes, and protecting a regular sleep schedule, especially in the week before an exam.

For international students adjusting to new time zones, demanding courses and a part-time job, this can be difficult. Yet treating sleep as part of studying, rather than as time taken away from it, may be one of the simplest ways to improve results.