There are few things as beneficial to your memory as a good night’s sleep. Let’s see why.
When you are tired it is difficult to pay attention and memory requires attention
In order to remember information, you need to pay attention to it. When you are tired you simply cannot pay attention as effectively as when you were well rested. This statement seems straightforward, but it begs another question: Why are you getting tired?
You may feel tired and have trouble paying attention, either because you’ve been awake too many hours and sleep pressure builds up, or even if you’ve been napping, because it’s the middle of the night and your circadian rhythm (your internal O’clock) tells you to sleep. In both cases, you have trouble paying attention and therefore losing your memory.
Does caffeine help?
Caffeine blocks chemical receptors in your brain so you temporarily cannot feel the pressure of sleep. So, caffeine can enable you to be more alert, more attentive, and better remembered. But as you probably know from your own experience, caffeine can only delay increasing sleep pressures, which eventually leads to overwhelming fatigue.
Get ready for new learning
As you learn new information during the day, it is temporarily stored in the hippocampus, a seahorse-shaped part of your brain behind your eyes. The hippocampus has a limited storage capacity. If you exceed this you may have difficulty adding new information or you may actually overwrite an old store with a newer one.
Fortunately, that doesn’t usually happen. Every night while you sleep, the connections between neurons (called synapses) shrink to reduce or eliminate the memories you don’t need – like what you had for breakfast last week and the clothes you used yesterday have worn. This selective pruning of synapses during the night prepares you to make new memories the next day.
Sleep to solidify memories
Sleep also helps us solidify the memories we want to keep, moving them from temporarily accessible memories to those we can recall years later. Memories of facts and skills both show greater retention over a 12 hour period, including sleep, compared to a 12 hour wake period. Much of this consolidation occurs during stage 2 sleep, a light sleep phase that most commonly occurs in the hours before you wake up. This means that if you wake up early without getting a full night’s sleep, you may affect your ability to capture your memories.
Connect your memories while you dream
Although you dream through multiple phases of sleep, your most interesting and vivid dreams usually occur during Rapid Eye Movement (REM) sleep, so called because your body is otherwise paralyzed while your eyes are moving quickly. During REM sleep, your newly consolidated memories are linked to your past memories, including those of your life as well as your library of facts and knowledge. This connection between your most recent memories and your previous memories and knowledge is one reason you may wake up to a problem with a new and valuable perspective – or maybe even a complete solution!
This actually happened to Dmitri Mendeleev, who struggled for months over how the atomic elements should be included in the periodic table. In a dream on February 17, 1869, he saw where all the elements belong and, after writing down his dreams, discovered that only one small correction was required.
You will feel better in the morning
Have you ever been terribly upset about something and at least the next day it felt a little better? Sleep can also degrade the emotions associated with painful memories while preserving memory content. This allows you to remember what upset you without having to relive the full emotional intensity of the event.
Do sleeping pills help?
Melatonin isn’t a traditional sleeping pill, but it can help regulate your sleep cycle if that’s the problem. Paracetamol can relieve minor pain that may keep you up at night. All other sleeping pills, whether prescription or over-the-counter, will calm you down and in fact, you make your memory worse, both for what you learned earlier that day and what you want to learn the next day! Non-pharmacological treatments for sleep are by far the best.
The final result
Would you like to maximize your memory, whether you’re studying for an exam, preparing for a customer interview, or looking forward to your 50th reunion? You are more likely to remember the information for the exam, documents for the meeting, and the names of your classmates if you go through the material you want to remember daily for several days, followed by a refresher seven to seven nine hours of sleep a night. Sleep well!