Do you ever feel as though your memory isn’t as sharp as you’d like it to be? Before you ascribe that fuzzy memory to age or the frenetic pace of daily life, try putting your head on the pillow for a good night’s rest. Sleep—how much you get, and how well you sleep—can have a powerful effect over memory.
What is memory?
When we talk about memory and its relationship to sleep, what do we mean? Memory is actually a series of complicated cognitive processes. We can look at memory broadly in three distinct phases:
Acquisition: taking in new information
Consolidation: storing information that’s been acquired
Recall: retrieving memory from storage
How does sleep affect it?
Sleep can play a role in helping—or hindering—each of these phases of memory. Sleeping well, and avoiding sleep deprivation, can make a real difference in your ability to take in new information—essentially, to learn. If you’ve ever tried to study for a test or complete a work project while short on sleep, you’ve experienced the obstacles that sleep deprivation can have on memory acquisition. Even a very short period of a lack of sleep can diminish your capacity to form new memories in everyday learning.
Sleep is also important to your ability to recall memories you’ve already made. Research indicates that recall of both short-term working memory, as well as long-term memory of different forms are impaired by lack of sleep. A sleep-deprived brain is less effective at memory retrieval, while staying well rested can help protect and improve this ‘remembering’ phase of memory.
While both memory acquisition and memory recall are influenced by sleep, it is the middle phase of the memory process—consolidation—that actually occurs during sleep itself. Memory consolidation takes new knowledge you’ve acquired and stores it for future recall and use. Memory consolidation that takes place during sleep not only secures memory for future retrieval, but also appears to free up the learning centres of the brain in preparation to take in new batches of information in the next waking day.
Scientists are still discovering how memory consolidation works during sleep, but the belief is that it occurs during several different stages of sleep throughout the night. Both slow-wave sleep (also known as deep sleep) and REM sleep are considered critical to the consolidation of different forms of memory. The architecture of a typical night’s sleep includes a greater share of slow-wave sleep during the first part of the night, and a larger proportion of REM sleep in the latter part of the night. In order to take full advantage of sleep’s positive effects on memory, it’s important to get a full night of rest on a regular basis.
When you’re under pressure—whether for a deadline at work, or an exam at school—keep in mind that you and your memory will be better served by getting a good night’s sleep, rather than pushing late into the night in hopes of cramming more information into an already-tired brain. Well rested, you’re more likely to feel better, and to remember more.