<figure id="attachment_479899" aria-describedby="caption-attachment-479899" style="width: 1512px" class="wp-caption alignnone"><a href="#" data-ident_hash="904c9800"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2026/09/65bb35eb053fcad3059e13ccd601fc07.jpg" alt=""></a><figcaption id="caption-attachment-479899" class="wp-caption-text">As I stroll through nature, I record whatever catches my eye or pops into my head, one after another, using the voice memo app on my smartphone. Since I’m not sharing these with anyone, I’ll freely weave together stories that lift my spirits.</figcaption></figure>
 In recent years, it has been pointed out that loneliness, much like obesity or smoking, may increase the risk of death and dementia. That said, in today’s world, we have smartphones, and social media allows us to stay connected with others at any time. Many people may think, “Loneliness has nothing to do with me” or “I’m physically and mentally healthy because I have connections with others.”
 But there’s a pitfall to that sense of security. Neurosurgeon Michihito Sugawara warns, “If you use your smartphone incorrectly, there’s a risk that you’ll keep causing damage to your brain without even realizing it.” Smartphones aren’t just for connecting on social media. In this article, we’ll introduce “ways to use your smartphone that are good for your brain”—practices you can start implementing right away in your daily life.
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<h2> Three Factors That Cause “Smartphone Brain Fatigue”</h2>
 ――I think communicating via social media on smartphones helps alleviate loneliness among seniors, especially those living alone…
 “People in the Reiwa era are more digitally savvy than ever before, but they’re experiencing not only the benefits but also the drawbacks. In particular, among the senior generation—whose ‘healthy life expectancy’ should, in theory, be increasing—an growing number of people are reporting symptoms such as ‘a lack of motivation,’ ‘trouble remembering names,’ and ‘a constant feeling of heaviness in the head.’
 Some of this forgetfulness and lethargy may not be solely due to ‘aging’ but could be caused by ‘how they use their smartphones’” (All quotes below are from Ms. Sugawara)
 ――It’s true that we’ve been hearing the term “smartphone brain fatigue” quite often lately.
 “Strictly speaking, ‘smartphone brain fatigue’ is not a medical term. However, it accurately describes a condition that many people today are experiencing. In the past, human fatigue resulted from moving the body itself, since both travel and labor were primarily performed using physical effort.
 Nowadays, desk work has become the norm, and physical fatigue has decreased. However, constant access to digital devices now causes the brain to work excessively, and this has become the new normal.”
 —Why does “smartphone brain fatigue” occur?
 “There are three main factors contributing to brain fatigue caused by smartphones. First, quite simply, there is ‘stimulation from light.’ The intense light emitted from smartphone screens—particularly blue light—suppresses the secretion of melatonin (a hormone that affects the body’s internal clock).
 As a result, sleep quality declines, leading to brain fatigue. This is because low levels of melatonin inhibit the function of the ‘glymphatic system’—the system responsible for removing waste products from the brain during sleep.
 Prolonged “dopamine-induced excitement” is also harmful to the brain. The striatum—the center of the brain’s reward system—releases dopamine (a pleasure chemical) every time we encounter new information from social media. This dopamine creates a desire in us to “see more.”
 As if to satisfy that desire, social media continues to provide new information. Faced with this unending flood of information, the brain becomes completely trapped in a search-reward loop. As a result, the function of the prefrontal cortex—which is responsible for concentration and decision-making—becomes dulled, and our ability to think deeply declines.”
 The third factor is “emotional volatility.”
 “Social media showcases the successes and happiness of others. Of course, there are days when we can genuinely rejoice and offer our congratulations. But depending on our mental state, there are also days when we unconsciously feel jealousy or inferiority. Since social media is also full of content that stirs up anger and anxiety, stress can build up over time.
 These daily emotional fluctuations gradually affect the autonomic nervous system and disrupt its balance. These three factors lead to ‘smartphone brain fatigue,’ manifesting as symptoms such as ‘insomnia,’ ‘irritability,’ ‘mentally foggy,’ ‘inability to concentrate,’ and ‘forgetfulness.’”
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<div data-friday-nextpage-lead=" The brain is in a state of excitement caused by dopamine"></div>
<figure id="attachment_479900" aria-describedby="caption-attachment-479900" style="width: 1440px" class="wp-caption alignnone"><a href="#" data-ident_hash="23b138c8"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2026/09/aba7edd8a72da4556b3b4f8d34773211.jpg" alt=""></a><figcaption id="caption-attachment-479900" class="wp-caption-text">Dr. Sugawara recommends that, instead of immediately looking up a word you can’t remember, you take at least 10 seconds to search your own “memory drawer.”</figcaption></figure>
<h2> Use Your Smartphone to Train Your “Output Brain”!!</h2>
 —So even when you think you’re just glancing at your smartphone, the dopamine-fueled excitement in your brain never stops, does it? It’s true—I’ve opened social media for no particular reason only to realize hours had passed. And I felt strangely exhausted afterward…
 “The brain’s dopamine release mechanism is a remnant from an era in our evolutionary history when ‘acquiring new information was advantageous for survival.’ Before the advent of civilization, humans increased their chances of survival by reacting quickly to unknown events.
 However, in modern times, this mechanism is overactive. The constant stream of news and social media updates continuously stimulates the brain, and as a result, the brain is prone to falling into a chronic state of ‘distraction.’”
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 ――Is it necessary to take the drastic step of “giving up your smartphone” altogether?
 “No, I don’t recommend such drastic measures. While it’s necessary to reevaluate our engagement with social media, I don’t think it’s necessary to completely cut ourselves off from smartphones. In fact, there are reports that for some people, being forced to give up their smartphones actually increases feelings of anxiety and loneliness and raises levels of cortisol, a stress hormone.
 In modern society, smartphones are already an integral part of daily life. Simply cutting them off entirely carries the risk of placing a burden on both your mind and body.”
 ――Is there a way to use a smartphone without tiring the brain?
 “Of course. The impact smartphones have on the human brain and mind can be either ‘poison’ or ‘medicine,’ depending on how they’re used. So far, I’ve explained the ‘poison’ aspect, but now I’d like to introduce ways to use them as ‘medicine.’ 　The key is shifting from an ‘input brain’ to an ‘output brain.’”
 —Please tell me some specific ways to shift to an “output brain.”
 “I recommend ‘taking a walk while recording your inner monologue.’ Every day, each of us encounters countless flashes of inspiration, emotional fluctuations, and even ‘fragments of memory.’ But most of them have already slipped away by the moment we notice them, never to return in the same form.
 Record those irreplaceable moments using your smartphone’s voice memo function (the ‘Voice Memos’ app on iPhone or the ‘Recorder’ app on Android). Recording your inner monologue isn’t just a simple way to keep a record—it’s also a multifaceted form of training for the brain. First, the act of speaking itself moves the muscles of the mouth and throat, stimulating the “motor cortex.” Next, hearing your own voice in real time activates the “auditory cortex.”
 Furthermore, as you strive to maintain the flow of your speech, your “working memory” (which functions like a notepad and workbench for the brain, simultaneously holding and manipulating information) works at full capacity to connect the preceding and following contexts. It is a highly efficient brain process that simultaneously mobilizes multiple areas related to language, emotions, and autobiographical memory.”
 ――You often see scenes in TV dramas where a famous detective or doctor discovers the truth while talking to themselves.
 “That’s because the experience of ‘hearing one’s own voice with one’s own ears’ serves as a powerful stimulus for the brain. It enables a deeper level of processing that simply thinking in one’s head cannot achieve.
 For seniors in particular, ‘taking a walk while recording oneself talking to oneself’ can be very meaningful. This is because more people are living alone, and opportunities to speak out loud are decreasing. With voice memos, you aren’t speaking to anyone else—you’re using your own voice and listening to it with your own ears—so it can be done anytime, anywhere.
 Moving your mouth and throat is also considered an important part of rehabilitation. People with Parkinson’s disease are sometimes encouraged to ‘talk frequently’ or ‘go to karaoke.’ That’s how crucial speech is for both the brain and the body.”
 ――I imagine some people might struggle to come up with ideas. What kind of things should they record while taking a walk?
 “Anything goes (laughs). You can simply describe what you see and hear during your walk, just as it happens. If you see a dog on a walk and think, ‘That’s cute,’ just put that feeling into words however it comes to you. If you notice a change in the seasons, say out loud, ‘I can feel the end of summer in the air’ or ‘An autumn-like breeze is blowing.’
 Don’t worry about ‘speaking well’ or ‘saying something interesting.’ Your smartphone has plenty of storage. Set aside any filters—like feeling embarrassed or thinking it’s boring—and directly voice and record whatever emotions or thoughts come to mind.”
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<div data-friday-nextpage-lead=" “Autobiographical Memory” in the Brain"></div>
<h2>If you reduce your input, you’ll gain clarity about your own life</h2>
 —You mentioned that this activates language, emotions, and—one more thing—autobiographical memory.
 “For example, while out for a walk, I might suddenly recall, ‘There used to be a ramen shop here.’ The taste of the ramen I ate there, the atmosphere inside the shop, who I visited with—by speaking these memories aloud, the ‘autobiographical memory’ in my brain is activated.It’s not just nostalgia; it also serves as training to strengthen your ‘ability to recall.’”
 —What precautions should I take to make “walking while recording my inner monologue” a habit?
 “Since you’re walking, I don’t recommend taking notes with a pen or typing on your smartphone for safety reasons. It’s also important to keep in mind that ‘the goal isn’t to keep it up indefinitely.’
 The moment you start thinking of this smartphone-based brain training as a ‘daily requirement,’ it turns from something enjoyable into a chore. This habit, which was meant to be beneficial, turns into a source of stress, and your smartphone reverts to being a ‘poison’ once again. Above all, it’s important to maintain an attitude of continuing at a pace that doesn’t strain you.”
 ――Finally, please share a message for our readers.
 “Let’s reduce ‘excessive input’—endlessly watching videos and scrolling through social media. Even if it’s information related to your favorite hobbies or the things you’re passionate about, constantly consuming it does nothing but harm your brain. In that state, your brain has no time to rest, and eventually, it will exceed its processing capacity and simply become overwhelmed.
 Your brain is better able to perform at its full potential when you don’t overload it with information. Reduce your input and turn your attention inward. Take a step back from the flood of information, and during those moments of daydreaming, essential questions like ‘What do I truly value?’ will naturally surface. Focusing your full mental energy on those things that matter most will greatly determine the quality of your life moving forward.”
 ――Thank you very much. I’d like to walk back to the station while recording my thoughts on this interview on my smartphone.
<figure id="attachment_479902" aria-describedby="caption-attachment-479902" style="width: 240px" class="wp-caption alignnone"><a href="#" data-ident_hash="50142b86"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2026/09/5815908cb739a77fcc2af0b299b037c2-1-rotated.jpg" alt=""></a><figcaption id="caption-attachment-479902" class="wp-caption-text"> In Mr. Sugawara’s recent book, *The Smartphone as Medicine: Good Habits for Your Brain After 50, as Taught by a Neurosurgeon* (Kawade Shobo Shinsha), he introduces various habits to stimulate the brain, in addition to this “soliloquy walk.”</figcaption></figure>
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 Interview and Text: Yutaka Sano 
Yutaka Sano: Freelance writer. His main areas of expertise include business and the humanities; he is active across various media—including magazines and the internet—primarily conducting interviews and writing articles. He is the author of numerous books.
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<a href="#" data-ident_hash="acd03e13"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2026/09/7337697f719bd40d7be05750105c1d95.jpg" alt=""></a>
 Michihito Sugawara
 Neurosurgeon. After graduating from Kyorin University School of Medicine, he worked at the National Center for Global Health and Medicine, specializing in emergency neurological conditions such as subarachnoid hemorrhage and cerebral infarction. In 2015, he opened the *Sugawara Neurosurgery Clinic*. He has established a style of “medicine based on life goals” and provides care that extends to supporting patients’ mental well-being and way of life.
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 Yutaka Sano, courtesy of Mr. Sugawara (profile photo)

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Instead of Using Social Media, You Should Record “Mutterings to Yourself”!? A Neurosurgeon’s Practical Guide to “Smartphone Use That’s Good for Your Brain”

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