Less than 7 Hours of Sleep, Frequent Napping, Feeling of Insomnia ─ Three Signs Reflecting the Risk of Brain Aging

Is a Sleepless Night Connected to the Future of the Brain?

"Recently, I can't fall asleep easily," "I find myself dozing off during the day," "I only sleep in on weekends"—such concerns are not uncommon for modern people. Work, household chores, smartphones, stress, aging. There are too many factors disrupting sleep, and many people dismiss sleeplessness as a "common ailment."

However, a new study published by a research team from the University of Arizona and others suggests that we need to reconsider sleep disturbances more carefully. According to the study, some common sleep habits were associated with imaging signs of brain aging.

The study focused on the following three points:

First, sleeping outside the recommended range of 7-9 hours. Particularly, those who slept less than 7 hours showed a tendency for higher white matter lesion volume in the brain. Second, frequent napping during the day. Third, the feeling of insomnia, such as difficulty falling asleep or maintaining sleep.

It's important to note that this study does not definitively state that these habits will inevitably age the brain. Rather, it found a statistical correlation between self-reported past sleep habits and subsequent brain MRI images. Nonetheless, using a large dataset of over 23,000 people, the study adjusted for factors that could affect the brain, such as blood pressure, smoking, and lack of exercise, and still found the three sleep habits noteworthy.

The Study Examined "White Matter Lesions," Scars on the Brain

The indicator used in the study is known as white matter hyperintensities or white matter lesions. These are changes observed in brain MRIs, reflecting small damages or changes occurring in the brain's white matter regions.

White matter acts like "communication cables" connecting various regions of the brain. An increase in lesions could potentially disrupt smooth information exchange. White matter lesions tend to increase with age and are known to be associated with cognitive decline and dementia risk.

In this study, participants reported their sleep behaviors, including sleep duration, napping, feelings of insomnia, unintentional daytime sleepiness, and snoring, between 2006 and 2010. Approximately nine years later, brain MRIs were taken to measure the volume of white matter lesions.

In the initial analysis, all five sleep behaviors were associated with a higher volume of white matter lesions. However, after considering factors related to brain vessels and lifestyle, such as hypertension, smoking, and physical inactivity, the three habits that remained strongly associated were "sleeping outside the 7-9 hour range," "frequent napping," and "feelings of insomnia." Snoring and unintentional daytime sleepiness did not remain as prominent associations after adjustments.

Is "Napping is Good for Health" a Misconception?

In this study, the part about napping likely garnered the most reactions on social media. Short naps have often been considered good for concentration, mood, and work efficiency. Many people actually feel refreshed by closing their eyes for about 15 to 20 minutes after lunch.

So, does this study claim that "napping is bad"?

In conclusion, it's not that simple. The questionnaire used in the study asked about the frequency of napping, without distinguishing the length, timing, whether the nap was planned, or if it resulted from an inability to sleep at night. This means that short, intentional power naps and long, frequent naps to compensate for insufficient nighttime sleep might have been grouped together.

Even if frequent napping was associated with white matter lesions, it might not be that napping itself negatively impacts the brain. Instead, it could indicate poor nighttime sleep quality, changes in physical condition, or some changes in brain or vascular health that lead to increased napping.

This is the part most prone to misunderstanding by readers. This study is not a "ban on napping." Rather, if daytime sleepiness is strong enough to necessitate naps, it should prompt a review of nighttime sleep, stress, sleep apnea, medication effects, blood pressure, and metabolic issues.

Sleeping Less Than 7 Hours Should Not Be Taken Lightly

Sleep duration is more intuitively understandable. Additional analysis by the research team found that those who slept less than 7 hours had more white matter lesions compared to those who slept within the recommended range.

Chronic sleep deprivation can lead to disruptions in attention, memory, and emotional control. In the long term, it can also affect blood pressure, blood sugar, inflammation, and metabolism. The brain doesn't just rest while sleeping; it engages in many recovery tasks such as organizing neural activity, consolidating memory, processing waste, and regulating immunity and hormones.

Of course, the necessary sleep duration varies from person to person. Some people can function well on 6 hours of sleep, while others still feel tired after 8 hours. However, even if you think you're fine with short sleep, you might just be accustomed to chronic sleep deprivation.

This study suggests that sleep duration should be considered not just as a lifestyle rhythm issue but as a factor potentially affecting future brain health.

The Feeling of Insomnia Might Not Be "Just in Your Head," But a Sign of Brain Health

The feeling of insomnia was also associated with a higher volume of white matter lesions. This includes difficulty falling asleep, waking up in the middle of the night, light sleep, and not feeling well-rested.

Insomnia is not just a subjective issue of "not being able to sleep and feeling miserable." It can lead to various problems such as decreased daytime concentration, mood depression, anxiety, accident risk, and worsening of lifestyle diseases. Moreover, accumulating studies like this one might make insomnia an important clue when considering brain aging and dementia risk.

However, the relationship between insomnia and white matter lesions is not necessarily one-directional. While sleeplessness might affect the brain, changes in the brain or blood vessels might also disrupt sleep. Alternatively, third factors like stress, pain, depression, anxiety, medication, lifestyle, and social isolation might influence both.

Therefore, there's no need to blame yourself for being unable to sleep. What's needed is to avoid making sleep a matter of willpower or determination. If sleeplessness persists, it's an option to consult medical institutions or experts rather than trying to cope with lifestyle improvements alone.

On SNS: "Is Napping Also Bad?" "It's Hard to Get 7 Hours of Sleep"

The reaction on social media to this news, as far as can be confirmed through public searches, was not explosive but centered on initial sharing by accounts interested in medicine, health, and gerontology, introducing the key points of the research. On LinkedIn, shares by medical professionals were observed, highlighting the association between sleep duration, napping, feelings of insomnia, and white matter lesions. On Facebook, posts sharing the research paper and university announcements were confirmed.

There are three major points of discussion that are likely to arise from general readers' reactions, and which often occur with such themes.

First, the confusion of "I heard napping is good for health, so which is it?" This is the most natural reaction. The idea that short naps help daytime alertness and the idea that frequent napping is associated with white matter lesions seem contradictory at first glance. However, they don't necessarily conflict. The issue lies not just in the presence of naps but in their frequency, timing, duration, and relationship with nighttime sleep.

Next, the realistic voice of "I can't sleep for 7 hours." For those dealing with childcare, caregiving, night shifts, long working hours, commuting, and smartphone habits, 7 hours of sleep might seem idealistic. News emphasizing the importance of sleep can sometimes make readers feel guilty. However, such research is not meant to blame individuals but should serve as material to reconsider whether society as a whole is cutting back on sleep too much.

The third point is the optimistic view of "If sleep can be improved, it might be a gateway to dementia prevention." Researchers also emphasize that sleep is a modifiable risk factor. While age and genetics can't be changed, bedtime, wake-up time, bedroom environment, caffeine, alcohol, exercise, and how naps are taken can be gradually adjusted.

When this topic spreads on social media, headlines alone can lead to extreme interpretations like "Napping is bad for the brain" or "Lack of sleep leads to dementia." However, the essence of the research is not there. It's about seeing sleep not as a whole but by breaking it down into specific behaviors like sleep duration, napping, and feelings of insomnia, revealing patterns related to brain health.

Points to Reconsider Starting Today

So, what should we do?

First, try recording your sleep duration. You might think you're sleeping for 7 hours, but in reality, you might be in bed for 7 hours while actually sleeping for a shorter time. Conversely, you might think you're sleeping long, but frequent awakenings could mean low sleep quality.

Next, observe your napping patterns. If naps are short, end early in the afternoon, and don't interfere with nighttime sleep, they might not be a big issue. However, if you find yourself sleeping long every day, napping in the evening or later, or unable to get through the day without a nap, it might be a sign of nighttime sleep issues or health conditions.

Additionally, if insomnia persists, check for smartphone use before bed, caffeine, alcohol, bedroom brightness, lack of exercise, and stress. The more you stress about sleeping, the harder it might become. If the difficult state continues for more than a few weeks, consulting an expert is also an option.

Sleep improvement doesn't have to be a dramatic reform. Wake up at the same time every day. Get sunlight in the morning. Avoid late afternoon caffeine. Keep the bedroom dark and cool. Don't keep looking at your smartphone in bed. Keep naps short and avoid them in the evening. These small adjustments might have long-term significance for brain health.

Sleep: A Modifiable Brain Health Habit

The important message from this study is that sleep is a "modifiable factor." Hearing words like brain aging and dementia might make some feel it's an unavoidable fate. However, while not everything can be changed, how we approach sleep can be reconsidered.

Of course, sleep alone cannot prevent dementia. Blood pressure, diabetes, exercise, diet, smoking, social connections, hearing, and mental health all play a role. Still, sleep is a habit repeated daily and directly linked to body and brain recovery.

Sleepless nights happen to everyone. There are days when naps help. What's important is not to overly fear a single instance of sleep deprivation but to notice if sleep disturbances are becoming chronic.

"Recently, my sleep pattern has changed," "Daytime sleepiness has increased," "I have consecutive nights of sleeplessness." Such small signs might not just be fatigue but messages from the brain and body. From an era of sacrificing sleep for productivity to one of maintaining sleep for healthy longevity. This study might serve as a catalyst for that shift.

Source URL

University of Arizona news release. Overview of the study, number of subjects, three sleep habits, association with white matter lesions, and researcher comments confirmed.
https://news.arizona.edu/news/struggle-sleeping-these-three-common-sleep-habits-tied-signs-brain-aging-u-study-finds

EurekAlert! published the same news release. Confirmation of publication date, DOI, research methods, paper title, and no conflict of interest.
https://www.eurekalert.org/news-releases/1131144

Information on the paper published in Alzheimer's & Dementia. Confirmation of paper title, authors, DOI, UK Biobank 23,377 participants, white matter hyperintensity volume in MRI, and summary of statistical results.
https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.71457

Information on the paper published by University of Arizona Experts. Confirmation of paper bibliographic information, authors, journal, abstract, and keywords.
https://experts.arizona.edu/en/publications/associations-of-sleep-behaviors-with-white-matter-hyperintensity-/

Neuroscience News article. Used for summary of research content, white matter lesions, explanations on sleep duration, napping, and feelings of insomnia, and confirmation of paper abstract.
https://neurosciencenews.com/sleep-habits-white-matter-lesions-30830/

CDC "About Sleep." Confirmation of necessary sleep duration for adults, health importance of sleep, and general points for improving sleep habits.
https://www.cdc.gov/sleep/about/index.html

LinkedIn public post. Used as an example of initial reactions on social media, sharing by medical professionals, and confirmation of reaction and comment numbers.
https://www.linkedin.com/posts/erwinloh_sleeping-outside-the-recommended-seven-to-nine-hour-activity-7468991937052692480-7W0c