From Scheherazade going on the longest bedtime storytelling spree in the 1,001 Arabian Nights to Freud delving into The Interpretation of Dreams to that seminal classic Goodnight, Moon, we all agree sleep is extremely important. But what does sleep actually do for you? Is it possible for sleep to actually improve your mental abilities while awake?
1. The Importance of Sleep for Your Body (and Brain)
Aside from keeping you from feeling like you’re about to collapse into your morning breakfast (lifesaving coffee and all), there are several other reasons why sleep is essential for a healthy body.
For one thing, studies have shown that a lack of sleep can lead to weight gain. In fact, research has shown that a lack of sleep is one of the biggest risk factors for obesity, which in turn is a huge risk factor for heart problems. A lack of sleep has also been linked to an increased risk of stroke and diabetes.
On the mental side, a lack of sleep can increase your risk of depression. On the flip side, a proper amount of sleep can be hugely beneficial. Sleep is essential for several vital brain functions. For example, REM sleep is connected with neuron communication. There is also evidence to suggest your brain does some “spring cleaning” while you’re asleep, removing toxins, recalibrating itself — and yes, perhaps boosting brainpower.
2. Defining Brainpower and Sleep
But what exactly does that mean? According to Professor Matthew Walker, the director of the Centre for Human Sleep Science at UC Berkeley, brainpower is all about our brain’s “learning capacity.” How well we are able to learn, focus on, memorize, and engage with new mental tasks are all components of “brainpower.”
This really reveals that “brainpower” is, essentially, a euphemistic term. As such, “learning capacity” is less about adding new “mental hardware,” as it were, than getting yourself in the best condition to maximize your potential.
3. How Does Sleep Impact Our Brainpower?
Critically, this isn’t done by “neuro-enhancement” pseudoscience but by resting your brain and getting it ready to learn. As Prof. Walker notes, “60–90 minutes of additional sleep boosts the learning capacity of the brain.” Our ability to learn is connected in part to sleep spindles, which are electrical pulses during REM sleep.
This accounts for around 25% of sleep time in normal adults, and can help consolidate procedural and declarative memory while you sleep. Declarative memory is devoted to tasks such as memorizing names, dates, facts, and other things we can describe in terms of language. Function-wise, declarative memory is linked to processing and learning things quickly.
Procedural memory, by contrast, is associated with long-term memory, motor skills, and learning “how to do something.” This typically relates to components of larger processes. Walking, talking, riding a bike, and playing a musical instrument are all examples of processes that can be done from memory without thinking about it. For example, a well-trained pianist doesn’t need to “think” about where the keys are when they play — they simply “know,” and that memorized long-term mental “knowledge” is part of procedural memory.
Critically, Stage 2 sleep, which happens during the second half of our sleep at night, is a particularly good time for the formation of new sleep spindles, which in turn can help boost declarative and procedural memory. This, combined with the brain’s ability to cleanse and refresh itself, helps put your brain in the best position to both make the most of your “learning capacity” and then encode that knowledge into declarative and procedural memory for long-term use.
4. Tips for Boosting Brainpower
As reported in Scientific American, slight boosts to your brain’s electrical waves can improve your memory. A German team discovered that running a weak electrical current through sleeping medical students’ brains helped them score better on word-recall tests. This study provided the first concrete evidence that oscillations of groups of neurons are not background noise neural activity but are essential to the formation and encoding of memory.
If you’re someone who likes falling asleep to the sound of rain pitter-pattering, you’re not alone — and it might actually be beneficial. A 2017 entry in Frontiers in Human Neuroscience posited that “pink noise” (low frequency sounds) such as rain or waterfalls can improve slow-wave sleep, with those who listened to it scoring three times higher on memory tests than before. However, there’s also evidence to suggest this is less about boosting any actual brain function and more about simply helping you sleep with all the benefits that it gives to your memory.
According to Harvard Health Publishing, brain foods for boosting mental performance include walnuts, leafy greens, fatty fish such as salmon, and berries rich in flavonoids such as blueberries.
Finally, a 2019 study in Current Biology has helped affirm the old idea that studying something you want to learn or memorize before going to sleep does indeed improve your chances of retaining the information. This is especially true for “verbal association information,” such as “word pairs.”
While you may not be able to “learn while you sleep” per se, you can ensure that your brain is ready to maximize your learning capacity while awake and encode as many declarative and procedural memories as possible while asleep.