Yanwen’s blog

7/5/2026 

Yesterday I read an interesting paper: "Distinct Effects of Long-Term Resistance Exercise on Cognitive Deficits, Neurotrophins, and Amyloid Pathology in Male and Female APP/PS1 Mice."

What the researchers wanted to know

Most studies on exercise and brain health have focused on aerobic exercise—walking, jogging, cycling, and swimming.

This study asked a different question:

Can long-term resistance training (strength training) also help protect the brain against Alzheimer's disease?

The researchers were also interested in whether males and females respond differently.

What they did

The study used a well-established mouse model of Alzheimer's disease. These mice develop amyloid-beta (Aβ) plaques, memory problems, and cognitive decline similar to some features of human Alzheimer's disease.

Both male and female mice completed a four-month resistance training program. Their "weight lifting" consisted of climbing a ladder while carrying progressively heavier weights attached to their tails—a standard method for studying resistance exercise in mice.

The researchers then evaluated learning, memory, activity level, brain growth factors, and amyloid plaques.

What they found

The results differed between male and female mice.

Female mice showed:

• Improved short-term memory

• Reduced hyperactivity

• Increased VEGF (vascular endothelial growth factor)

• Reduced amyloid-beta levels

• Reduced amyloid plaque burden

In other words, female mice showed less Alzheimer's pathology.

Male mice showed:

• Improved learning and long-term memory

• Increased BDNF (brain-derived neurotrophic factor)

• Increased IGF-1

• Reduced hyperactivity

Interestingly, although male mice showed clear cognitive improvement, their amyloid plaques did not decrease significantly.

Why these findings make sense

The results are biologically plausible.

For years, neuroscientists have known that exercise increases important growth factors such as BDNF, IGF-1, and VEGF. These molecules support neuron survival, promote new neural connections, improve blood supply, and enhance the brain's ability to learn and adapt.

Resistance exercise also reduces inflammation and improves insulin sensitivity—both of which are increasingly recognized as important factors in Alzheimer's disease.

Perhaps the most intriguing finding was that males and females appeared to benefit through different biological pathways. Female mice showed greater reductions in amyloid pathology, while male mice appeared to benefit primarily through increased neurotrophic support. This fits a growing body of evidence suggesting that Alzheimer's disease does not develop in exactly the same way in men and women, likely because of differences in hormones, metabolism, immune responses, and vascular biology.

If confirmed in humans, this could eventually lead to more personalized approaches to prevention and treatment.

An important limitation

This was a mouse study, not a human study.

Many Alzheimer's treatments that produced impressive results in mice have ultimately failed in clinical trials. Mouse brains are much simpler than human brains, so these findings should be viewed as promising rather than conclusive.

In addition, Alzheimer's disease involves far more than amyloid plaques. Modern research recognizes that tau protein, inflammation, vascular disease, metabolism, genetics, and other factors all interact in complex ways. Simply reducing amyloid has not consistently translated into meaningful cognitive improvement in humans.

My takeaway

Although this single study cannot tell us what resistance training does in people, it fits well with a much larger body of research.

Over the past two decades, regular exercise has consistently been associated with lower dementia risk, larger hippocampal volume, better executive function, healthier blood vessels, improved glucose regulation, and better overall brain health.

It also complements other research on healthy cognitive aging, including studies on music, lifelong learning, reading, social engagement, good sleep, hearing preservation, and blood pressure control.

Rather than looking for one "magic bullet" against dementia, the evidence increasingly points toward a lifestyle portfolio. Music, reading, writing, learning new skills, aerobic exercise, resistance training, and meaningful social interaction may each protect the brain through different mechanisms. Together, these healthy habits may have additive effects over a lifetime.

Finally, keep in mind that, a healthy brain is not built by any one single habit. It is cultivated over decades through physical, intellectual, and social engagement.

7/4/2026

I came across an interesting study today:

"What Is the Association Between Music-Related Leisure Activities and Dementia Risk? A Cohort Study"(2025)

The researchers followed 10,893 Australians aged 70 or older who did not have dementia at the start of the study. They examined three types of music-related activities:

• Listening to music

• Playing a musical instrument

• Doing both

What they found

Compared with people who listened to music rarely or never, those who reported always listening to music had:

• 39% lower risk of dementia

• 17% lower risk of cognitive impairment without dementia (CIND)

People who often played a musical instrument had about a 35% lower risk of dementia. Those who both listened and played also showed lower risks.

Frequent music listeners also maintained better memory and overall cognitive function over time.

The study concluded:

"These results highlight music as a promising and accessible strategy to help reduce cognitive impairment and delay the onset of dementia in later life."

An important caution

This was an observational study, meaning it found an association, not proof of cause and effect. We still don't know whether music itself reduces dementia risk, or whether people with healthier brains are simply more likely to engage in music throughout life.

Where music might help

Although the exact mechanism remains uncertain, several explanations are biologically plausible.

Listening to—and especially performing—music engages multiple brain systems at the same time, including hearing, memory, attention, emotion, movement, and fine motor coordination. This widespread activation may help build what neuroscientists call cognitive reserve: the brain's ability to compensate for age-related changes.

Music is also associated with reduced stress, improved mood, increased body movement, and the stimulation of autobiographical memories—all factors linked to healthier brain aging.

My takeaway

Over the years, I have written about the benefits of learning foreign languages, reading, and cultivating intellectual humility through lifelong learning. These activities share something important with music: they all keep the brain actively engaged.

Increasingly, research suggests that no single activity prevents dementia on its own. Rather, healthy brain aging appears to result from a combination of mentally stimulating, physically active, and socially engaging habits. Music fits naturally into that broader picture.

One of its greatest advantages is this. Almost anyone can begin listening to music today, regardless of age. It is enjoyable, inexpensive, and carries virtually no downside.

Finally, our brains, much like our bodies, thrive when they continue to be challenged. Whether through music, reading, learning a new language, or meaningful conversation, keeping the mind engaged may be one of the best investment we can make for the years ahead.

7/3/2026

I wanted to record this encounter before its freshness faded.

On July 1, a clinician from our health insurance company came to our home for a routine health assessment. She was highly professional. Originally from South Korea, she had immigrated to the United States about ten years ago. Her story immediately reminded me of one of my former Korean students, who also came to America 10 years ago. Like my former student, she communicated well enough in English for her work, but I still found myself listening carefully to understand her.

Our conversation began when she asked whether we had any relatives nearby. I told her that both of our children live in Brooklyn and that we are expecting our first grandchild this month.

She clapped her hands and exclaimed, "This is so perfect!" There was such genuine joy in her reaction that I was curious. So I asked about her own life.

She told me she was in her early forties, single, and all alone in the United States while her parents remained in Korea. She also remarked that in Korea, "you have to be young and pretty to get a good job."

For the past two days, that brief conversation has lingered in my mind. I think it's because, before anything else, she was an immigrant, alone and far from home.

In that moment, I wasn't just talking to a healthcare professional. I was talking to someone who had left her home country all by herself, built a life in a foreign land, learned a second language, and was living thousands of miles away from her family. Her story brought me back to my own early years in America, when my family was far away and communication was difficult and expensive. It is, in many respects, the common experience of first-generation immigrants—a story of leaving behind the familiar world, learning to navigate a new culture and language, and building a life from the ground up.

Her spontaneous delight that my children live nearby suddenly made sense.

In both Chinese and Korean culture, family occupies a central place. Having children nearby, watching them begin families of their own, and becoming a grandparent is not simply another life milestone. It represents continuity across generations. Perhaps that was what she meant when she said, "This is so perfect."

Perhaps I should be grateful. We often appreciate what we have only after seeing it through someone else's eyes.

7/2/2026

Yesterday I discussed the Peloponnesian War and Thucydides' famous observation that "War is a violent teacher," comparing some of his insights with what happened during China's Cultural Revolution. Before continuing, here are a few basic facts about the war.

• Location: The eastern Mediterranean

• Period: 431–404 BC (27 years)

• Main issue: Fight for hegemony over the Greek world

• Outcome: Athens lost its maritime empire and dominance in the Aegean, bringing its Golden Age to an end. Sparta emerged as the leading Greek power.

• Major alliances:

  • Athens led the Delian League, which consisted of roughly 150–200 member states.

  • Sparta led the Peloponnesian League, with about 30–40 allies, including Corinth, Thebes, and Megara.

Now let me continue with yesterday's discussion.

3. Fear reshapes human behavior

Thucydides repeatedly emphasizes the role of fear—fear of enemies, fear of being suspected, and fear of appearing insufficiently loyal. Under such pressures, people often found themselves doing things they would never have imagined in ordinary times.

The Cultural Revolution also created an atmosphere of pervasive fear. Remaining silent could be dangerous, yet speaking against the prevailing political climate could be more dangerous. Many people's choices were constrained by fear that they perceived.

4. Social trust erodes

Healthy societies depend on trust—trust in our families, colleagues, neighbors, institutions, and communities. Periods of prolonged conflict and social chaos gradually destroy that trust.

People begin asking themselves, "Who might report me?" or "Whom can I safely trust?" Once those questions become part of everyday life, social relationships are fundamentally altered. Rebuilding trust afterward can take years, even generations.

5. Circumstances shape behavior—but do not determine it

Perhaps Thucydides' deepest insight is that extreme circumstances exert tremendous pressure on human behavior.

That does not mean everyone responds in the same way.

Even during the Cultural Revolution, some actively participated in persecution, some quietly protected those under attack, some kept their heads down in order to survive, and some accepted great personal risks to act according to their principles.

Circumstances shape behavior, but they do not determine it completely.

That is why Thucydides remains remarkably relevant today. More than simply writing about ancient Greece, he was identifying enduring patterns of human behavior that can emerge whenever societies experience prolonged fear, violence, or institutional collapse.

This reminds me of Aleksandr Solzhenitsyn's famous observation:

"The line dividing good and evil cuts through the heart of every human being."

The two thinkers complement each other. Thucydides emphasizes the immense power of external circumstances; Solzhenitsyn reminds us that individuals retain moral agency even under extraordinary pressure.

Ultimately, the larger question is not simply what war does to people. It is this:

What happens to human beings when the structures that sustain civilization—law, trust, stable institutions, and ordinary routines—begin to collapse?

War is one way that can happen. Revolution, civil conflict, state failure, famine, and other forms of prolonged upheaval can produce similar conditions. When those foundations weaken, fear replaces trust, survival instinct begins to outweigh moral and principle, and civilization itself proves more fragile than we often imagine.

That is why Thucydides still speaks to us nearly 2,500 years later.

More on this book later.

7/1/2026

When we moved from Kansas to the New York area, I had to part with many of my books. One of them was The History of the Peloponnesian War by Thucydides. I had intended to read it for years, partly because of the now-popular phrase "the Thucydides Trap," but never got around to it.

Recently I borrowed Donald Kagan's The Peloponnesian War from our local library. As I read it, something other than the geopolitical lessons captured my attention. I came across one of Thucydides' most famous observations:

"War is a violent teacher; it brings most people's characters down to the level of their circumstances."

The more I read, the more I understood what he meant.

According to Kagan, the Peloponnesian War devastated Greek society. It destroyed lives and property, intensified political and class divisions, fractured alliances among the Greek city-states, and ultimately weakened their ability to resist conquest from outside.

Even more striking was the brutality the war unleashed. As the conflict dragged on, anger, fear, and the desire for revenge steadily eroded the restraints of civilization. Prisoners were maimed or killed. Some were thrown into pits to die of thirst and starvation. Others were cast into the sea to drown. Innocent children were murdered. Entire cities were annihilated—the men executed, the women and children sold into slavery. During periods of civil war, fellow citizens slaughtered one another for days on end.

Violence also transformed the moral fabric of society. As Thucydides observed, words themselves changed their meaning. Reckless audacity came to be praised as courage, while moderation was dismissed as weakness. Religion lost much of its restraining influence. Truth and honor disappeared. Trust collapsed as communities became divided into hostile factions.

That is the deeper meaning of Thucydides' famous observation.

He is not arguing that human beings are inherently evil. Rather, he is suggesting that extreme circumstances profoundly change human behavior. In times of peace, people can afford to be generous, patient, civil, and principled. But during war, famine, or social upheaval, fear, deprivation, and uncertainty push many people toward actions they would previously have considered unthinkable. As he put it, war becomes "a violent teacher," bringing people's character down to the level of their circumstances.

Reading this passage inevitably brought to mind China's Cultural Revolution.

Although the two events were very different in their historical origins and political contexts, the patterns of human behavior show striking similarities.

The first is the breakdown of the most basic moral restraints.

Thucydides observed that prolonged conflict changes not only people's behavior but also their moral standards. Actions once regarded as shameful come to be accepted—even celebrated—because the surrounding circumstances have changed.

The Cultural Revolution displayed a similar pattern. Children publicly denounced their parents. Students relentlessly attacked their teachers. Friends informed on friends. Neighbors turned against neighbors. Behaviors that would have seemed unimaginable only a few years earlier became normalized under intense political pressure.

The people themselves had not suddenly become different. Rather, the environment had changed—and with it, what society rewarded, tolerated, or demanded.

The second similarity lies in the transformation of language.

Thucydides wrote that "words had to change their ordinary meaning."

Political labels became weapons. Virtues and vices were redefined according to factional loyalty.

The same phenomenon can be seen during the Cultural Revolution. Terms such as "revolutionary," "counterrevolutionary," "bourgeois," "class enemy," and "capitalist roader" acquired enormous political power. Language no longer merely described reality; it defined loyalty, determined guilt, and justified violence and persecution.

Once language changes, people's perception of reality often changes with it.

Think of this timeless question: What happens to ordinary human beings when the structures that sustain civilization begin to collapse? That's the question Thucydides was asking 2,400 years ago, and it's why his work still feels remarkably modern.

I'll continue exploring these parallels tomorrow.