When Moving More Isn’t Enough

This Week’s Research Highlight

“The Greeks understood that the mind and body must develop in harmonious proportions to produce a creative intelligence.”

President Kennedy spoke these words in an address given more than sixty years ago, reminding the country that movement isn’t just for the body — it fuels the brain, too.

Yet decades later, we’re still struggling to convince ourselves — and each other — that moving more is essential for keeping both body and brain resilient.

And the stakes have only grown on that front.

Modern work and leisure pull us into stillness for hours on end. Surveys suggest that Americans spend up to 13 hours of their waking day sitting, locked in front of screens or behind the wheel. Even our own minds conspire against us, favoring rest over movement at every turn.

So, we do what we can to compensate. We carve out time for workouts and count our steps, hoping that bursts of exercise can make up for all those static hours.

But that raises a question that feels increasingly relevant in an aging population: can regular physical activity really offset the physiological toll of so much sitting, not just on our body, but on our brain?

A new study from Vanderbilt set out to find an answer. In a group of older adults who defined the stereotype of sedentary aging, researchers tracked how much sitting alone might reshape the brain, regardless of how much physical activity they got.

Inside the Study

To probe how much sitting shapes brain health — and whether staying active can buffer that toll — researchers at Vanderbilt turned to a group of 404 older adults, most in their early 70s, and tracked them for up to seven years.

What made this sample remarkable was how active they were: On average, they logged more than 60 minutes of moderate-to-vigorous physical activity per day, with 87% meeting or exceeding the CDC’s recommended 150 minutes of moderate-to-vigorous physical activity per week. That is a stark contrast to most folks in that age group; it has been reported that fewer than 3% of older Americans meet public guidelines for physical activity.

Yet the researchers were after something else: the time spent not moving.

For seven days straight, participants wore triaxial accelerometers on their wrists — sensors that captured every flicker of movement in three dimensions. A validated algorithm, calibrated specifically for older adults, parsed the data second by second, tallying up hours spent still. Sitting quietly at a table or slouched in a chair, these brief moments of stillness aggregated into a measure of sedentary time, with sleep meticulously excluded.

And activity tracking was just the start.

At various intervals across the 7-year follow-up, participants underwent high-resolution 3T MRI scans to map the brain’s architecture: total gray matter, the vulnerable hippocampus, and a signature pattern of cortical thinning that has been tied to Alzheimer’s disease. Cognitive performance was gauged through a battery of neuropsychological tests — memory, language, attention, and more. This too was repeated over the years to trace changes, not just single moments.

To layer in genetic risk, the team also genotyped participants for the APOE-ε4 allele, a genetic variant linked to Alzheimer’s, of which roughly one in four Americans carry at least one copy. This enabled them to examine whether the toll of sitting might be greater in those already biologically predisposed to neurodegeneration.

All told, the researchers assembled something quite unique in this field: longitudinal data linking how much time people spend sitting with changes in brain structure, cognitive function, and genetic vulnerability — and in a group that was far more active than average.

It opened a window into a key question: can being physically active offset the harm of prolonged sitting on the brain?

Structural Brain Changes: The First Signs of Trouble

The first cracks showed up in the brain itself.

Recall that this was an unusually active group. These people were often logging more daily movement than their peers would manage in a whole week. But even in them, sitting left a clear mark.

In those who logged more sedentary time, brain scans revealed thinner cortex in the entorhinal cortex, middle temporal lobe, and inferior parietal cortex — regions known to wither early in Alzheimer’s disease. Scientists call this pattern the “AD signature,” an ominous footprint of decline.

Greater sedentary time was linked to thinner cortex in brain regions most vulnerable to Alzheimer’s disease, a pattern known as the “AD signature.”

But that was just a snapshot in time.

Over the next several years, the picture became clearer. Participants who sat more at the start of the study lost more volume in the hippocampus, the part of the brain that builds and retrieves memories. This erosion occurred regardless of how much physical activity they logged — pointing to sitting itself as an independent risk, not merely the flip side of inactivity.

Cognitive Changes and Genetic Risk

This structural deterioration translated into real slips in thinking and memory.

More sitting time meant steeper declines in episodic memory — the kind of memory that lets us hold on to conversations, appointments, and personal moments. It also meant slower performance on language tests and more sluggish processing speed, that flicker of mental agility we rely on every day to juggle competing thoughts or follow a fast-moving conversation. And this effect persisted even after accounting for education and physical activity.

Greater sedentary time was linked to poorer episodic memory performance.

Finally, the genetic backdrop added another layer. About a third of the participants carried the APOE-ε4 variant, which raises the risk of Alzheimer’s. For them, the damage associated with sitting was even greater: smaller gray matter volumes across key brain regions as well as shakier performance on visuospatial and naming tasks. Perhaps unsurprisingly, sedentary time hits harder when your genes have stacked the odds against you.

But the key takeaway here wasn’t really about genetics. It was that sitting itself carries a real cost. Even in people who met — and often crushed — the current standard for daily physical activity, more hours spent sitting meant more wear and tear on the brain.

How Sitting Starves the Brain

We’ve long known that movement — and the absence of it — shapes our heart health.

The first clear signal came in the 1950s, when Jeremy Morris studied workers in London’s transportation system. Drivers, locked behind the wheel all day, had twice as many heart attacks as the conductors who spent their shifts on their feet.

Average annual rates of first clinical episodes of coronary heart disease among London bus drivers and conductors (1949–50). Despite similar ages, drivers — who sat for most of their shifts — had higher rates of angina pectoris, coronary occlusion, and cardiac mortality than conductors, who spent their workdays on their feet. Table from Morris et al, 1953.

Why does sitting take such a toll? At the heart of this effect is blood flow.

Every minute we’re upright and moving — even just shifting weight or standing in line — our muscles contract, squeezing veins and pushing blood back to the heart. That constant movement stirs up shear stress inside blood vessels, a mechanical nudge that keeps them elastic, open, and healthy.

But sitting still flips that switch. Blood flow slows. Shear stress collapses. And the endothelial cells lining our arteries — the same cells that regulate nitric oxide and keep vessels supple — begin to lose their edge.

Clinical trials have captured this shift in real time. Just three hours of sitting can shrink the arteries in the legs, stiffen their walls, and slash the production of nitric oxide, the molecule that tells blood vessels to widen. Day after day, low shear stress and stagnant blood flow chip away at vascular health.

This hits the brain especially hard. The brain demands a rich and unbroken supply of oxygen and glucose. Indeed, a quarter of every heartbeat’s output goes there. When shear stress drops, the delicate network of vessels feeding the hippocampus and cortex begins to lose its flexibility. Less blood flow means less fuel. Neurons start to sputter.

For this reason, decreasing brain blood flow has been linked to accelerated cognitive decline, and people who have lower cerebral blood flow have been shown to be more likely to go on to develop dementia years later.

And here’s the paradox: these vascular changes from sitting are not fully reversed by bouts of physical activity alone. For instance, people logging seven hours of moderate-to-vigorous physical activity every week saw their cardiovascular mortality risk double if they also spent more than seven hours a day sitting in front of the TV.

When we sit still for too long, the blood vessels that feed the brain stop getting the signals they need to stay healthy. And as we saw in the Vanderbilt study, once those pipes begin to fail, it doesn’t take long for memory and thinking to follow.

Bringing the Findings Home

This study drives home a powerful point: it’s not just how much we move, it’s how long we spend still. Even in people who exceed physical activity guidelines, long stretches of sitting carve out their own distinct toll.

So what’s the path forward? More than anything, we want to avoid prolonged, uninterrupted sitting.

1. Create movement triggers. Use the natural rhythm of your day to prompt movement. Finishing an email, wrapping up a task, or starting a meeting? Let those transitions be your cue to stand, stretch, or walk for a minute. Movement becomes part of the flow, not an interruption.
2. Keep up the exercise. Physical activity remains essential — especially more intense movement. There’s growing evidence that harder exercise, like HIIT, may offer unique brain-protective benefits, spurring the release of myokines and other signaling molecules that nurture neurons.
3. Intentionally break up sedentary time. Target the long, uninterrupted blocks of sitting that build up silently throughout the day. Set alarms to remind yourself to get up, stretch, or move around every 30 to 60 minutes, even if it’s just for a minute.

That’s exactly what our InTUNE approach is designed to do.

InTUNE — Integrative and Opportunistic Training — weaves short, bodyweight movement breaks into your work rhythm: a handful of exercises between tasks, after an email, or before a meeting. It’s not just about hitting a step count or a new PR. It’s about breaking the sedentary cycle, increasing total daily activity, and giving your brain the steady pulse of blood and oxygen it needs to stay sharp.

Because preserving the brain’s vascular lifeline depends on moving not just more, but more often.

Summary: In a 7-year prospective study of 404 older adults, researchers tracked how sedentary time — measured by wrist-worn accelerometers — shaped brain health over time. Although 87% of participants met exercise guidelines, averaging over an hour of moderate-to-vigorous activity daily, prolonged sedentary time still predicted worse outcomes. Those who sat more had thinner cortex in Alzheimer’s disease–vulnerable regions, faster hippocampal atrophy, and steeper declines in episodic memory, language, and processing speed. These findings suggest that prolonged sitting independently harms brain structure and cognitive function, even in highly active older adults.

Random Trivia & Weird News

🛒 When shopping carts first hit the supermarket scene in 1937, customers hated them.

These days, it’s hard to imagine a grocery trip without one. But when Sylvan Goldman unveiled his cart design at his Humpty Dumpty supermarket in Oklahoma City, shoppers were supremely unimpressed.

Men thought they were too girly. Women thought they too closely resembled baby carriages. “I’ve pushed my last baby buggy!” exclaimed one offended shopper.

It took store models strutting around with carts to finally convince the skeptics. Turns out, even the simplest inventions sometimes need a little salesmanship.

Source: National Museum of American History

Podcasts We Loved This Week

• Josh Turknett and Tommy Wood: Can a long layoff really boost your performance? Via Better Brain Fitness.

• Donald Weaver: It’s unlikely a magic bullet will ever cure Alzheimer’s – maybe a magic shotgun can. Via The Conversation Weekly.

Products We Like

Oura Ring

A small, lightweight ring that does more than count steps.

The Oura Ring tracks body temperature, heart rate, and activity patterns around the clock — pinpointing moderate-to-vigorous activity as well as those long sedentary stretches. Unlike a lot of wrist-worn devices, it is comfortable enough to wear in bed and lasts 4–7 days on a single charge.

A super practical way to see how your daily movement — or lack thereof — adds up.

humanOS Catalog Feature of the Week

Daily Performance & Physical Activity

This course reveals how physical activity fuels brain performance—not just in the long run, but within minutes.

You’ll learn:

• How exercise builds mitochondrial powerhouses in your brain, not just your muscles
• Why high-intensity movement enhances focus and task-switching
• The role of BDNF in learning, memory, and mental adaptability
• How short movement breaks restore blood flow and sharpen thinking

Whether you're training for a new PR or trying to beat brain fog, this course shows how movement drives performance from the inside out.

To Access:

1. Log in to humanOS.
2. See Programs in navigation on the left-hand side
3. Click Daily Performance Program.
4. Scroll down to Daily Performance and Physical Activity.

Wishing you the best,