How Sleep Affects Memory Improvement

Optimized-Dollarphotoclub_36056926It’s a curious thing that human beings, and most other animal species, are driven to regular periods of inactivity and unconsciousness.

What could be less evolutionarily beneficial than a stretch of eight hours during which you can’t hunt, defend yourself, or reproduce? Not to mention working on your memory improvement.

All jokes aside, the fact that we are driven to sleep is an indication that sleep has an important purpose in our biology.

And yet, the precise mechanisms of sleep remain largely mysterious. The exact reasons why we require sleep, and what happens during sleep, are areas of current research.

One thing is for certain: lack of sleep leads to an array of social, financial, and health-related costs. Indeed, the fatality rate of sleepiness-related car crashes is similar to that of driving under the influence (Goel et al 2009). What’s more is that prolonged sleep deprivation leads to death for many studied species (and presumably humans) (Cirelli et al. 2008).

Despite these realities, a full 20% of adults are not getting enough sleep (Goel et al 2009). It’s a common practice in our culture to praise those who can work the most and sleep the least.

However, research indicates that this attitude is misguided. Lack of sleep has important negative implications for cognition. Sleep deprivation puts pressure on your entire cognitive apparatus, and has the potential to affect your memory.

After this article, you may be convinced that a nap is in order.

What Exactly Is Sleep?

Over 85 years, an average person will sleep 250,000 hours, which is equal to 10,000 full days (Scullin et al 2015).

But what is sleep, really?

It is commonly believed that sleep is a continuous period of a complete loss of awareness. But in actuality, sleeping is not one continuous state and a sleeping person does not lose total awareness. Instead, they alternate between reduced awareness of the external world and a complete loss of consciousness (Gudberg et al 2015).

From here, sleep is typically classified into two categories. The first is non-rapid-eye-movement (NREM) sleep and the second is rapid-eye-movement (REM) sleep (Bryant et al 2004).

NREM sleep happens during the early moments of falling asleep. As the name suggests, there is little to no eye movement during NREM sleep. Dreams are rare during this stage, your body is not paralyzed as in REM sleep, and mental activity is still “thought-like” (Bryant et al 2004). This is the stage during which some people will sleep-walk.

The role of NREM sleep is to conserve energy, cool the body and brain, and promote immune function.

Following NREM sleep, a person will fall into REM sleep, where rapid eye movements can be observed. This is where the majority and the most vivid dreams occur. Your body is paralyzed, which is an adaptation to prevent you from acting out your dreams. You will periodically wake up – which some researchers feel serves as a way to survey the environment (Bryant et al 2004). These mini-awakenings are typically not remembered.

The Devastating Consequences Of Sleep Deprivation
On Memory Revealed

As you sleep, you will cycle between NREM and REM sleep four to five times during the night.

By understanding our sleep patterns, it becomes evident that there is much more that happens during sleep than simply being unconscious. The broad overview given here just scratches the surface of the complex world of sleep.

For all of its complexity, sleep serves essential functions. For example, a sleep-deprived person suffers from many ailments, including:

  • A weakened immune system (Bryant et al 2004).
  • Reduced wakefulness – microsleeps during wakeful hours after sleep deprivation (Cirelli et al. 2008).
  • Compromised cognition.

The compromised cognition experienced during sleep is all too familiar for many of us. We all know that after a poor night’s sleep, we are groggy and we tend to think more slowly.

When it comes to memory, the essential role that sleep plays is more pervasive than most realize.

Sleep Plays a Key Role When it Comes to Your Memory

According to Robert Stickgold of Harvard Medical School in a recent interview with Robinson Erhardt, “I don’t know of any memory type of memory that isn’t enhanced by sleep.”

There are three basic memory stages.

The first is called acquisition or encoding. This is the process of collecting the information or processes that you’d like to memorize. An example could be re-reading the dates and prominent figures in a history book. This is called “declarative” memory, and is the memory of facts and information. Another example of memory is procedural memory. This is memory of how to do something. This could be anything from learning how to ride a bike or learning how to play the piano.

The second step is consolidation, where the information you’ve absorbed become stable in your mind. It is at this stage that memories are formed in your mind.

Finally, you must be able to recall memories for them to be useful. Thus, the final stage in memory is remembering something during your waking hours.

Numerous studies have indicated the importance of sleep for the second stage, memory consolidation. A good night’s sleep can help you recall facts and information, as well as solidify skills that you’re trying to learn.

Under the current scientific understanding, sleep is absolutely essential to memory. We require sleep to file information collected during our waking moments, in our minds. In doing so, we are able to recall newly acquired information (Ellenbogen et al. 2006).

For example, learning the guitar requires that you memorize hand movements as well as notes. This is called procedural memory. Long term sleep has been specifically found to help with procedural memory formation (Diekelmann and Born, 2010).

Sleep Shifts Info Around In Your Brain

Sleep also serves to reorganize new memories. During sleep, the brain will access new information and make links with previously absorbed information.

This helps segment and associate relevant parts of a complex memory to previous memories. While solidifying new information in your mind, this aids in the creativity process. This is because the brain will sometimes associate new information with old information in unexpected ways, thereby leading to novel insights (Diekelmann and Born, 2010).

Scientists also believe that we “replay” our previously learned information and skills during our sleep. Experiments have been conducted on animals and humans after they have been trained on a particular task. During sleep, the same parts of the brain that were active during the training exercises, were active while sleeping as well. This is because the brain will repeat the actions during your sleep (Diekelmann 2014).

Sleep is essential to memory. One study not only found poor memory recall in sleep deprived individuals, but also found that they recalled false memories. That’s right, you are more likely to remember untrue information following sleep deprivation (Diekelmann 2008).

In other studies, those that slept, recalled more and performed better on cognitive tests than those who stayed up. Looks like those all-nighters weren’t the best idea after all. Here are more tips on studying for tests in addition to getting a good rest.

How to Use Sleep For Memory Enhancement

Getting a good eight hour sleep has been shown to benefit memory (Diekelmann and Born, 2010). But what about sleep that occurs outside of your regular nightly routine, such as power naps?

Good news nappers! Research has also pointed to memory improvement even for shorter naps.

In a study of 29 undergraduate students, one hour naps were found to benefit factual recall. However, the memory of procedures, that is, memory of how to perform actions, was not improved. The study concluded that more complete periods of rest were necessary for the proper learning of memory (Tucker et al 2006).

Even more stunning is that even very short naps seem to have a positive effect on memory of facts and information. A study compared different nap durations, as well as staying awake. They found that even a micro-nap of six minutes enhanced memory recall. The study concluded that although longer naps improved recall more than very short naps, very short naps still have significant benefits (Lahl et al 2008).

Ultimately, it seems that if you’re looking to improve your memory of facts and information, naps are in fact helpful. However, if you are trying to learn the keyboard, a longer sleep time is what you really need.

In terms of the optimal or minimum amount of sleep that you’d need, that is still unclear. More research is needed.

However, if for whatever reason you can’t afford a full-night’s rest, a nap might help to keep you going.

How to Get a Good’s Night Sleep

Now that we know the importance of sleep, you may be wondering how you can get the absolute best sleep possible. After all, most of us do not have the benefit of being able to sleep and take naps whenever we’d like. That’s why it’s important to learn how to get the highest quality sleep during the time you have available.

Here are some tips to improve your sleep and help you get to sleep faster:

  • Only use your bed for sleeping and sex. Try to avoid using electronics, watching TV or eating in bed. This might associate these activities with being in a bed and prevent you from being able to fall asleep.
  • Avoid long naps during the day. Although I’ve mentioned that naps can enhance memory, it’s important to restrict napping because they can also prevent sleep. Take no more than a 25 minute nap during the day, or avoid them altogether.
  • Remove all lights and sounds from your bedroom. Buy light-blocking curtains if necessary. Use a regular alarm clock instead of your cell phone.
  • Do not drink or consume caffeine for at least six hours before bed. Be careful, coffee isn’t the only substance that contains caffeine. Tea, soda, and even chocolate contain caffeine that you should avoid before trying to fall asleep.

Memory enhancement is a tricky business and there are a myriad of ways you can do it. Whether it be food, meditation, or drugs, everyone has a preferred method.

Regardless, everyone needs to sleep. Since sleep plays such a key role in memory retention and recall, you might as well make the best of it. Make sleep a priority in your daily life.

Contrary to popular belief, sleep isn’t for the weak. Sleep is for those with great memory improvement goals.

Further Resources

Bryant, Penelope A., John Trinder, and Nigel Curtis. “Sick and Tired: Does Sleep Have a Vital Role in the Immune System?” Nat Rev Immunol Nature Reviews Immunology (2004): 457-67. Web. 18 Jan. 2016.

Cirelli, Chiara, and Giulio Tononi. “Is Sleep Essential?” PLoS Biology PLoS Biol (2008). Web. 18 Jan. 2016.

Diekelmann, Susanne. “Sleep for Cognitive Enhancement.” Frontiers in Systems Neuroscience 8 (2014): 46. PMC. Web. 18 Jan. 2016.

Diekelmann, Susanne et al. “Sleep Loss Produces False Memories.” Ed. Jan Lauwereyns. PLoS ONE 3.10 (2008): e3512. PMC. Web. 18 Jan. 2016.

Ellenbogen, Jeffrey M, Jessica D Payne, and Robert Stickgold. “The Role of Sleep in Declarative Memory Consolidation: Passive, Permissive, Active or None?” Current Opinion in Neurobiology (2006): 716-22. Web. 19 Jan. 2016.

Goel, Namni et al. “Neurocognitive Consequences of Sleep Deprivation.” Seminars in neurology 29.4 (2009): 320–339. PMC. Web. 18 Jan. 2016.

Gudberg, Christel, and Heidi Johansen-Berg. “Sleep and Motor Learning: Implications for Physical Rehabilitation After Stroke.” Frontiers in Neurology 6 (2015): 241. PMC. Web. 18 Jan. 2016.

Lahl, Olaf, Christiane Wispel, Bernadette Willigens, and Reinhard Pietrowsky. “An Ultra Short Episode of Sleep Is Sufficient to Promote Declarative Memory Performance.” Journal of Sleep Research J Sleep Res (2008): 3-10. Web. 19 Jan. 2016.

Scullin, Michael K., and Donald L. Bliwise. “Sleep, Cognition, and Normal Aging: Integrating a Half-Century of Multidisciplinary Research.” Perspectives on psychological science : a journal of the Association for Psychological Science 10.1 (2015): 97–137. PMC. Web. 18 Jan. 2016.
Nature Reviews Neuroscience 11, 114-126 (February 2010)

Tucker, M., Y. Hirota, E. Wamsley, H. Lau, A. Chaklader, and W. Fishbein. “A Daytime Nap Containing Solely Non-REM Sleep Enhances Declarative but Not Procedural Memory.” Neurobiology of Learning and Memory (2006): 241-47. Web. 19 Jan. 2016.

12 Responses

  1. Anthony, I think your relocation project would be served by being a “Snowbird”. Just follow the Sun.

    Buenos Aires, Argentina
    Barcelona or Valencia, Spain
    Medellín, Colombia

    ¡Feliz Senderos!

  2. Thanks, Anthony. I’ve been focusing on learning how to memorize a shuffled deck of cards. I noticed that on weekends (when I take a full night’s sleep) I perform better than the rest of the week. In fact, as the week progresses, I tend to score lower and lower then make an improvement on the weekend. Since making this observation (and snacking on walnuts?) I’ve evened out my sleep regime which has made a noticeable flattening of my weekly progress which is still improving.

    1. Thanks for this post, Jim. I wish my food sensitives didn’t mess with exploring the power of foods that improve memory like walnuts. I’m jealous! 😉

      It’s interesting that you’ve noticed this slump across the span of the week. Is there a way you could sleep more during an upcoming week to see how results improve? Or perhaps during a vacation? It would be great to track and see what happens. I’m sure the results would be quite positive.

  3. I’ll start by saying up front that I usually have no problem falling asleep as soon as my head hits the pillow. I try to limit myself to just seven hours during the week and eight on the weekend. Still can’t believe that I used to drink coffee right up until bedtime, although I have weened myself off that bad habit. I also enforce a no electronic devices rule at least one hour before lights out.

    Naps in the middle of the day are also a guilty pleasure, although I need to set an alarm or else I’ll inevitably over sleep.

    Read somewhere that people should sleep with the curtains open so that the body can get the sensation of night light. Not sure if it’s true but it can’t hurt.

    While sex and sleep may be the main activities to be done in a bed. I still enjoy reading a good novel in the lead up to going off to the land of nod.

    Schlaf gut und träum etwas schönes!

    1. I like reading in bed too and have recently been dipping into Hard-Boiled Wonderland and the End of the World by Haruki Murakami. It has a lot to do with memory and its surreal nature has been inspiring some extra-stimulating dreams lately.

      The night light idea is interesting, but I suppose that depends on where a person is located. For example, there’s a marked difference between the night light of stars and the night light of street lamps. Having lived in cities for so long, I’m always happily astonished to see the starry sky when visiting my parents in Canada. Civilization has given us so much, but robbed us of a billion diamonds with the same stroke …

    1. Yes we want to see.
      But we also want to Know How to NOT fall asleep while Reading.
      I have problems with this every day.

      1. Great question, Marius.

        Can you tell me more about the situations in which you do fall asleep? Are you reading in bed, for example, or at a desk?

        In the meantime, here are some suggestions in no particular order of importance. Try them all! 🙂

        1. Don’t read in bed.

        2. Read in a cafe, library or some place well lit with other people around. If noise makes concentration difficult, bring ear plugs.

        3. Take notes and highlight while reading. Even if you don’t need the info, this activity will help you stay awake. I recommend organizing your notes on index cards so you can shuffle the information for writing essays and whatnot. If you have them spread in a linear fashion throughout a notebook, it can be hard to find the important points – which is also tiring.

        (I talk more about the topic of preparing information using index cards in the Magnetic Memory Method podcast titled How To Memorize A Textbook.)

        4. Take regular breaks. Try to take them before the feeling of tiredness kicks in. Dave Farrow was on the podcast and recommended studying in blasts as short as five minutes. I haven’t tried this approach myself, I must admit, but it’s well worth experimenting with.

        5. Organize your reading schedule. For example, you can have preparation days (organize what you’re going to read), reading days (actually reading the material) and reviewing days (going through your notes). For bonus points, write little essays about what you’ve read – and of course memorize the key points using a Memory Palace.

        6. Shut off any thoughts about not liking a book. Sometimes we have to read things we’d rather not. When that happens, we often start complaining about how boring the book is or worrying about wasting time. Such thoughts cost energy and can be deeply tiring.

        7. Set a goal. If you’re not using a timing method by setting a clock, you can set a goal of 5-10 pages before you take a break. Knowing exactly how far you’re going to read might help you keep alert.

        8. Consider reading How To Read A Book. It will teach you a lot about using your reading time to create knowledge instead of just acquiring it.

        9. Check if you’re falling asleep while reading, or growing sleepy during other activities. You may need to consult with your doctor because the issue may not pertain to reading alone.

        10. Eat foods that improve memory. Many of them also provide you with clean energy that promote alertness.

        11. Take cold showers. I’ve been doing the Wim Hoff Method for several months now and highly recommend the cold shower part for alertness. The breathing exercises are fantastic too, but nothing beats a cold shower for waking up and feeling refreshed. (In fact, I’m going to take one just as soon as I finish this response!)

        12. Use the Human Charger that I mentioned in the episode. It’s helped me a lot.

        13. Just let yourself fall sleep without feeling guilty or badly about it. I know that this isn’t your goal, but it’s worth throwing this point into the mix.

        I’ll never forget Eckhart Tolle’s point about procrastination. Since we’re all going to do it from time to time, why do we psychologically punish ourselves so much? And since so many people have the opposite problem and struggle to fall asleep, maybe you have a blessing in disguise – so long as you can get the reading required of you finished.

        As a side note, I often fall asleep during movies. Throughout my life, I’ve had friends, a wife and countless girlfriends get annoyed by this harmless “flaw” (especially since I worked as a Film Studies professor for so long).

        In truth, I love falling asleep during movies. For some reason it’s very comforting to me and I sometimes go to the movie theatre just to fall asleep. I did this with the latest Star Wars earlier this week and it was fantastic.

        Because here’s the thing: We can take up books from where we left them again and movies are easy to navigate through or start again from the beginning.

        Anyhow, I hope these tips help. Let me know how it goes for you with staying alert while reading as you move forward. 🙂

  4. Sir can I really memorize 80 pages of poetry with memory palace my house is so small. And the other thing is if I want to learn other stuff what should I do sir I cannot reuse the memory palace.

    1. Thanks for these questions.

      Have you completed the free MMM Memory Improvement Kit? Working with just one Memory Palace is impractical and not part of this teaching.

      The truth is that you can reuse Memory Palaces, but I do not recommend doing so. You should have multiple Memory Palaces to fully experience the power of this technique.

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Anthony Metivier is the founder of the Magnetic Memory Method, a systematic, 21st century approach to memorizing foreign language vocabulary, names, music, poetry and more in ways that are easy, elegant, effective and fun.

Dr. Metivier holds a Ph.D. in Humanities from York University and has been featured in Forbes, Viva Magazine, Fluent in 3 Months, Daily Stoic, Learning How to Learn and he has delivered one of the most popular TEDx Talks on memory improvement.

His most popular books include, The Victorious Mind and… Read More

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