22 Dec 2016
The link between sleep and memory was first established years ago1. However, since scientists are not entirely sure how our brains retain memory, the exact relationship between sleep and memory is still being investigated, and is not completely understood.
What we do know is this: more sleep can mean better memory.
The consensus among scientists is that sleep enhances your brain’s ability to remember information and, therefore, to learn.
A lack of sleep negatively impacts your ability to secure memories and can interfere with learning. Sleep—and different sleep stages in particular—appear to allow the brain to re-process newly acquired information into more lasting memory.
During this process, memories made during the day are said to be “consolidated,” or crystallised into long-term, stable memories. The quality and quantity of our sleep affects our memory, no matter how old we are.
Research shows that sleep can enhance motor memories2. Motor memory, also known as procedural memory, refers to the ability to learn physical skills like riding a bike, throwing a baseball, mastering a video game or playing an instrument. Sharp motor memory can help people who are training for a sport or learning new musical pieces on the piano. If you get enough sleep, your skill-based memories become sharper. Motor memories can even benefit from an afternoon nap, which is often dominated by light sleep.
Declarative memory refers to the ability to store and recall facts, such as all those dates, places and events you had to memorise in history class. Research3 has found that memories of recently learned facts strengthen if sleep occurs between learning and testing. During deep sleep, (slow wave sleep), declarative memory appears to be given a particular boost.
Perceptual memory can also be enhanced by sleep. It has been suggested that during REM sleep, the brain processes sensory learning4, which can lead to better understanding of the visual, auditory, spatial, and emotional conditions that surround us.
Even though sleep can be very beneficial for strengthening memories, it is not a great time for new memories to form. As the body transitions between sleep and wakefulness, the brain’s ability to retain new information shuts down.
Case in point: Have you ever woken up late in the morning only to realise that you had turned off your alarm without realising it?
You probably fell asleep again so quickly that your brain had no time to store the memory of the alarm ringing. This may also be the reason why you don’t always remember your dreams, or they tend to fade very quickly in the morning. The transitions between sleep and wakefulness make the formation of new memories a challenge.
The importance of sleep for memory shows that the better-quality sleep you have, the better your memory is likely to be. To understand more about how your sleep is affected, download the “Unlocking the Pillars of Health” eBook. By improving the way you sleep, you can also look to improve your memory.