Time spent in daylight could lower the risk of dementia and offer extra benefits for people at particularly high risk, new research suggests. The findings, published in General Psychiatry, could provide a low-cost way to support brain health.
Having less than 0.7 hours of bright daytime light per day was a stronger predictor of dementia than six traditional risk factors. Moderately bright natural light exposure—equivalent to an overcast day outdoors—was linked with a 16% reduction in the risk of dementia.
“Daytime light exposure may serve as a novel indicator of dementia risk,” said researcher Hongliang Feng, PhD, from Guangzhou Medical University in China. Natural cycles of darkness at night followed by bright light during the day are fundamental to entrain circadian rhythms. These regulate physiology, behavior, and cognition, with circadian disruptions common among people with dementia.
Noting that modern lifestyles limit daytime exposure to natural light, the researchers investigated exposure to day- and nighttime light using actigraphy devices that track body movements with built-in light sensors.
The study included 87,577 UK Biobank participants who wore accelerometers on their wrists to measure physical activity and natural light exposure for seven days. Over a median follow-up of 8.1 years, 741 of these people (0.85%) developed dementia.
Higher daytime light, both in terms of average exposure and the duration in bright light, was significantly associated with a lower dementia risk. Daytime light exposure above 1000 lux—a moderately bright light level equal to an overcast day outdoors—was associated with a hazard ratio of 0.84 for dementia. Longer exposure to brighter light of at least 0.70 hours with at least 5000 lux was linked with a further risk reduction, and a hazard ratio of 0.83.
In exploratory analyses, circadian rest-activity rhythms (CRAC) and brain structures mediated up to a third of this association, supporting the idea that improvements in circadian rhythms may have contributed to these results. Dementia protection from light exposure was stronger in people with high levels of nighttime light exposure, those with a “night owl” evening chronotype, or who carried the APOE ε4 allele, with a risk reduction of up to 41%.
Having more than 0.7 hours per day of bright daytime light of at least 5000 lux outperformed the established dementia risk predictors, including alcohol consumption, obesity, air pollution, hearing loss, use of vitamin D supplements, and traumatic brain injury.
However, nighttime light showed no significant association with dementia risk.
The findings point to the importance of higher daytime light exposure in reducing the chances of dementia and offer a simple, cost-free way to reduce this risk.
“Practical implementation pathways could include optimizing indoor lighting at home, community‐based outdoor activity promotion programs, and workplace lighting modifications designed to increase daytime light exposure, such as ensuring adequate illumination and access to natural light,” the researchers suggested.
They added: “Our findings underscore a more pronounced protective association of daytime light exposure in individuals with higher average nighttime light exposure, an evening chronotype, or APOE ε4 carrier status.
“In other words, these findings suggest a targeted approach to mitigate dementia risk by increasing daytime light levels for these populations.”
Research led by Edith Cowan University in Australia suggests the impact of genetic mutations that impact Alzheimer’s disease risk are influenced by a person’s sleep habits.
As reported in the journal Alzheimer’s & Dementia, the researchers confirmed links with aquaporin-4 gene (AQP4) variants and changes in brain volume, atrophy and cognition linked to Alzheimer’s disease.
The investigators also showed how long people sleep, how long it takes them to fall asleep, how often their sleep is disturbed, and how good or poor their sleep is overall contributed to the effect of these mutations.
“Our study shows that individuals carrying certain AQP4 variants showed faster grey matter loss when they reported shorter sleep,” said study co-author Ayeisha Milligan Armstrong, PhD, a researcher at Edith Cowan University, in a press statement.
“It’s not just which genes you carry—it’s how those genes interact with the world around you. The same variant can look protective or detrimental depending on how someone is sleeping. That’s important, because sleep is one of the few modifiable factors people can actually act on.”
Researchers now think the brain gets rid of amyloid‑beta using a kind of plumbing system that washes waste away along the outside of blood vessels. In this system, fluid moves through the spaces around blood vessels, helped by tiny water channels called aquaporin‑4, encoded by AQP4, which sit on the parts of astrocyte cells that wrap tightly around those vessels.
“Given that AQP4 has been identified as an important mediator of brain amyloid beta clearance, variation within the AQP4 gene has been investigated in relation to neurodegenerative diseases and their associated phenotypes,” write the authors.
“A bi-directional relationship has been observed between suboptimal sleep and increasing brain amyloid beta accumulation…Importantly, a previous study utilizing data from the Australian Imaging, Biomarker and Lifestyle cohort reported that the relationship between sleep and cross-sectional brain amyloid beta burden was moderated by genetic variants in AQP4.”
To investigate this link further, the researchers studied 351 cognitively normal people already showing ongoing build‑up of brain amyloid‑beta on positron emission tomography (PET) imaging. They genotyped the group for 13 mutations in the AQP4 gene and also assessed sleep duration and quality, brain volume, amyloid burden and cognition scores.
Several AQP4 variants interacted with sleep measures to predict gray‑matter atrophy, brain ventricular volume, white‑matter volume, and cognitive decline. For example, people carrying certain variants who also had shorter sleep duration were more likely to have faster grey‑matter loss, and other variants magnified the impact of poorer global sleep quality on ventricular enlargement in the brain.
One variant showed a direct association with better global cognitive performance and two other variants seemed to be linked to less cognitive decline as sleep disturbances increased.
“We’ve known for a while that poor sleep and Alzheimer’s risk are linked,” said first author Tenielle Porter, PhD, also a researcher at Edith Cowan University.
“What this shows is that rather than assuming everyone at risk follows the same pathway, a more targeted and personalized approach to Alzheimer’s prevention may be needed. But we’re not at the point of recommending genetic testing; our findings need replication in larger and more diverse cohorts.”
BackgroundDespite strong evidence for cognitive behavioral therapy for insomnia (CBT-I), uptake remains constrained by poorly understood cognitive, attitudinal, and practical barriers. This study examined determinants of willingness to enroll in sleep improvement programs among adults at risk of sleep disorders—including insomnia, obstructive sleep apnea, and comorbid psychological distress—attending a tertiary sleep clinic in China.MethodsA cross-sectional knowledge-attitudes-practices survey was conducted among 2,661 adults attending the sleep and behavioral medicine outpatient clinic at Ganzhou Hospital-Nanfang Hospital, Southern Medical University, Ganzhou, Jiangxi, China, between February 2022 and June 2025. Willingness to enroll in a structured sleep improvement program was assessed alongside sleep health knowledge, perceived need, CBT-I versus medication effectiveness beliefs, telehealth acceptability, clinical severity (Insomnia Severity Index, Epworth Sleepiness Scale, STOP-Bang), psychological symptoms (PHQ-2, GAD-2), perceived barriers, and sociodemographic characteristics. Multivariable logistic regression identified independent predictors of willingness to enrollment, with secondary analyses evaluating model discrimination and testing prespecified interactions.ResultsAmong 2,661 participants (median age 45 years, 56.5% female, median ISI = 13), 1,386 (52.1%) expressed willingness to enroll. Univariable comparisons showed no significant differences between willing and not-willing groups across demographics, clinical characteristics, or barriers (all p>0.05). However, multivariable modeling revealed that when considered simultaneously, cognitive-attitudinal factors emerged as significant independent predictors, suggesting complex interactions rather than simple bivariate associations. In multivariable models, perceived need (OR = 1.20, 95% CI: 1.16–1.25, p<0.001), beliefs that CBT-I is more effective and durable than sleep medication (OR = 1.12, 95% CI: 1.08–1.16, p<0.001), sleep health and treatment knowledge (assessed by a six-item knowledge score) (OR = 1.09, 95% CI: 1.05–1.13, p<0.001), and anxiety symptoms (OR = 1.07, p=0.005) positively predicted willingness. Paradoxically, depression symptoms (OR = 0.94, p<0.001) and insomnia severity (OR = 0.93, p<0.001) inversely predicted willingness. Model discrimination was modest (AUC = 0.543, 95% CI: 0.504–0.590). Time (mean 3.54) and cost (3.44) were most severe barriers but showed no independent association with willingness (p>0.05).ConclusionCognitive-attitudinal factors (perceived need, CBT-I beliefs, knowledge) independently predicted enrollment willingness, whereas demographics and practical barriers did not. Depression and insomnia severity paradoxically reduced willingness, creating an inverse care law. However, poor model discrimination and measurement of stated willingness rather than actual enrollment limit conclusions. Prospective validation and motivational enhancement strategies for patients with depression are needed.
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<![CDATA[Pediatric experts link insomnia and mental health, favor CBT over sedatives, and warn against cannabis for sleep.]]>
It’s cold, it’s very, very noisy, and—if I can be quite honest with you—I’m not feeling super relaxed.
I’m currently around 300 meters, or 1,000 feet, beneath the North Sea, in a dark, dank cave. It smells weird. And I am increasingly aware of the pressure from millions of tons of seawater just above my head, pushing down with a force of more than 500 pounds per square inch. Picture a baby rhino standing on a postage stamp.
Only fabulous engineering is keeping me from being crushed, drowned, disappeared. My safety goggles are foggy.
Just a few hundred meters away, someone is about to blow up a giant rock wall. Luckily, earlier that day I was given a full safety briefing, and I’ve got a special hard hat on. “Don’t worry—if you don’t make it, we’ll have your stuff sent back to your office,” geologist Anne-Merete Gilje tells me, straight-faced. Ah, Norwegian humor.
“It’s kind of a lifestyle. You have to be a little bit crazy to work underground all the time.”
Niclas Brusehed, tunnel foreman, Implenia
I’m in this odd situation under the iconic fjords of Norway to visit what will soon become the world’s longest and deepest subsea road tunnel, called Rogfast (short for “Rogaland Fixed Link”). I want to understand how you make something as audacious as a 26.7-kilometer (16.6-mile) highway that sits 390 meters (1,280 feet) below the sea at its deepest point. And also—at a time when it can feel hard to get anything done, especially in the US—to reassure myself that ambitious engineering is still possible. That we can still make things.
The Norwegians already have the world’s longest subsea tunnel, the 14.4-kilometer Ryfylke, though Rogfast will dwarf it. Their expertise has attracted attention from Japan, Spain, Morocco, and even a number of US states, whose representatives were due to visit the site in May, just weeks after I went. They, too, want to know how Norway does it.
The answer: tons of explosives.
The entire endeavor feels like an obstinate refusal to give in to physics and geology. “It’s always exciting,” Niclas Brusehed, a tunnel foreman at Implenia, a Swiss firm involved in the project, tells me. “Every blast creates a new world.” There’s not just the blasting of the tunnel itself—although that is an epic project on its own—but an immense logistics challenge involving huge ventilation shafts, extreme pressure, underground roundabouts, and the complex Norwegian geology. Oh, and the water. So much water.
“This is the longest continuous blast on the sea,” says John Olaf Østerhus, assistant project manager at Implenia. “Never been done before. We can’t buy a book to see how we do this.”
All right, time to fish my phone out of my safety suit—don’t want to forget this.
On another planet
Arriving at the rock face where the tunnel hits seabed feels like being on the moon. It’s a huge slab of stone at the end of a long, dark, wet, wide passageway that’s lit (barely) by electric lights. Giant vehicles carting tons of rocks rumble past periodically, and we pull to the side of the road to let them by.
Rescue chambers are spread throughout the tunnel network.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
Workers clock in for 12-hour shifts, 6 a.m. until 6 p.m., deep in the bowels of the Earth where no natural light can reach. Twelve days on, 16 days off. They eat their lunch at a table in this damp cave surrounded by portacabins plastered with safety notices. “It’s kind of a lifestyle,” says Brusehed, laughing. “You have to be a little bit crazy to work underground all the time.”
These crazy engineers are here to make tunnels the Norwegian way. The nation frequently uses what’s known as the drill-and-blast method instead of the tunnel-boring machines that are more typical elsewhere. This approach offers more flexibility for long, complex operations with varied rock types. Each blast adds about five to six meters to the tunnel.
Rogfast is being built inward from the ends to speed things up. The construction company Skanska is leading from the north, coming from the island of Vestre Bokn; Implenia has joined a company called Stangeland to tunnel from Randaberg in the south, which is where I am. Both teams use multiple laser scans each day to consistently measure their orientation and check that the tunnel is exactly where it should be. The two ends should meet sometime in 2029, with no more than just a few centimeters of deviation.
The caves are like towering cathedrals, scattered with rubble.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
Norway has constructed more than a thousand kilometers of tunnels over the past several decades. The depth and length of these make the best efforts to date of Elon Musk’s Boring Company—a mere 2.7-kilometer tunnel in Las Vegas that is just 3.6 meters wide—look rather pathetic. The country’s spectacular setting makes such builds necessary; while Norwegians are proud of having the second-longest coastline in the world after Canada, getting up and down the west coast requires multiple ferry rides between islands, which can move extra slowly when the weather’s bad.
After it’s completed, which is scheduled to happen in 2033, Rogfast should help eliminate two ferry routes and cut the five-hour journey between the southwestern cities of Stavanger and Bergen by 40 minutes. It will funnel four lanes of traffic deep beneath the fjords of Boknafjord and Kvitsøyfjord, and at one section a relatively scant 50 meters of rock will separate the drivers speeding through the tunnel from the bottom of the North Sea. There are also, delightfully, two undersea roundabouts located 220 meters below sea level.
But the first job is to contend with all that water.
The never-ending battle
Subsea tunneling is defined by a constant, ultimately unwinnable battle with the ocean. The sheer weight of the sea above you, and the crushing pressure, means the water will always find a way in. “It’s the volume and the pressure that’s the biggest risk,” says Ole Magne Rønning, project leader for Implenia/Stangeland.
So before tunnel engineers blow stuff up, they need to check for leaks. Into the rock face ahead of them, they drill a number of narrow holes that go 25 to 30 meters deep to see how much water comes through. Even a small probe can unleash a torrent within seconds, says Rønning. When road traffic eventually rumbles through these tubes, water will still trickle from the rocks; it will be redirected into mini reservoirs dotted throughout the tunnel network before being pumped back out.
Since stopping the water entirely is impossible, the game is instead to push it away as best you can. If the leakage in front of the rock face exceeds a certain limit—around four liters per hole per minute—then the next stage is “grouting”: pumping a mixture of cement-like sludge into new holes that fan out in the ceiling above and around the face. Ideally, you address the leaks that are ahead of you; “it’s a lot more difficult to stop a leak that’s behind you,” says Rønning.
At one point deep below the sea, I chat with Tarald Johan Nomeland, the project’s grouting specialist. He’s big and bearded, perhaps one of the most Norwegian-looking men I’ve ever met. He stands, towering above me, and shakes my hand in his giant bear-like paw. Grouting is in Nomeland’s family; his dad did it too. He loves it. “There’s not necessarily just one solution to a problem,” he says, eyes flashing with delight as he describes fighting the interminable battle with the water. “There may be many solutions.”
The amount of grouting needed determines how fast the project can move. On the Skanska side, for example, some weeks the face moves 30 meters; others, as few as 10.
This isn’t made any easier by the rock itself. The seabed around Norway was shaped by glaciers during the Ice Age. As the ice retreated, it dragged softer rock with it, carving out the fjords for which the nation is so famous. But this legacy makes digging subsea tunnels particularly gnarly. Much of what’s left is the hard, difficult-to-break stuff.
And it’s not just one type of rock, either. There are “big wide areas where we don’t know what’s down there,” says Gilje, the geologist who is a project manager for the Norwegian Public Roads Administration, which is in charge of the entire project. Before any construction started, boats took core samples from the seabed along the planned tunnel route. Seismic surveys from the ocean surface—like those that look for oil in the region—helped fill in the gaps.
Each kind of rock presents its own challenges, so the engineers “have different techniques for different problems,” Gilje explains. For example, they found that one southern section contains a lot of phyllite. Phyllite is considered “nice” to work with. It is formed from a combination of shale, siltstone, and mud over time and is pretty compact, with few cracks to let water through. Its compact nature means it requires more explosives per blast, however. It also contains a lot of quartz, which is toxic when released into the air during blasting. So workers wear monitors to measure their exposure, and a curtain of water sprayed in front of the rock face helps prevent too much from drifting into the tunnel.
The northernmost part of the route, meanwhile, is made mostly of solid granite and a similar rock called gneiss. Both are hard but contain fractures that allow the seawater to trickle through.
The rock type can also change over just a short distance. So during the dig, every 80 meters or so, an engineer sends sound waves through the face to expose its secrets and help evaluate its structural integrity. The rock is graded on a scale of 1 to 5, with 5 being the worst and least stable. “When you are reaching class 5, then it’s almost like soil. It’s not rock anymore,” says Rønning.
This investigation informs the kinds of structural supports each section will need—from steel rods that fan out above the rock face like an umbrella, for the strongest rock, to reinforced-concrete arches that hold up the weakest. To seal everything off, the team sprays a substance called “shotcrete,” liquid concrete mixed with reinforced-steel fibers, onto the walls throughout. A plastic membrane and concrete panels are fitted later.
“It’s going to be a very safe tunnel,” Gilje says. “It’s going to last for 100 years.”
Strange dangers
While I may not be brave, at least I don’t get seasick. Back at the surface, I board a small ferry that putters and sloshes its way from the mainland to Kvitsøy, a sparsely populated municipality made up of 365 separate islands and islets—something its 550 or so inhabitants are very proud of, even though most of these islands are uninhabited chunks of rock.
For the next few years, Kvitsøy’s population will experience a tiny boom as its largest island hosts a semipermanent encampment of contractors and engineers working on what is probably the most complex part of the Rogfast project: the giant ventilation shafts that will sit roughly halfway along the tunnel’s length to bring fresh air into the entire network, and remove the stale air in turn.
It’s also one of the reasons why road tunnels are much more complex than rail tunnels. Cars pump out fumes that have to be vented away. During construction, fresh air flows in via huge plastic tubes suspended from the ceiling, but eventually, Rogfast’s air will come in through two nine-meter-wide shafts that will bore down from Kvitsøy’s surface: one to bring it in, one to take it out.
Hundreds of steel rods are fitted to support the ceiling and walls.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
Creating these shafts is a wild process. First, narrow boreholes are drilled from the ground down into the tunnel 210 meters below the surface. A vertical drill rig is then pulled up through the hole from the bottom, widening the shaft to 2.4 meters as it ascends.
Then explosives are set off on the island’s surface, bashing down through the rock to widen the shaft. A large digger pushes the resulting debris down the narrower, not-yet-exploded length of shaft below, sending rocks barreling toward the tunnel at the bottom like socks tumbling down a laundry chute. Trucks haul away the fallen rocks. This process happens in stages, repeating at regular intervals, opening up the passage a bit deeper with each pass. Once it’s all done, steel rods are installed in the shaft’s walls to keep it secure.
Down below, I stand beneath one of the narrow guide holes for one of the two ventilation shafts. The ceiling soars overhead—a strangely beautiful cathedral, cragged and shadowed by lamplight.
Besides poisonous air, the epic nature of these engineering projects throws up other surprising dangers. For example, Rogfast will take about 30 minutes to drive through. It doesn’t seem that long, but the project’s designers worry that the monotonous environment may lull some drivers to sleep.
Engineers faced this problem with Ryfylke—which, as the current longest subsea road tunnel, has been a testing ground for its bigger sibling. It relieves the tedium with a large hall that opens up in the middle of the tunnel, lit by colored lights that change each day. When Rogfast is finished, artists will be invited to do something similar, using lights, colors, and shapes to keep drivers alert.
Then there are the environmental risks. What is there to do with all the loose rock created by the blasts? The engineers predict 8.5 million cubic meters’ worth. That’s enough to fill more than 2,500 Olympic-sized swimming pools. The solution is to bring it back to the surface, where it can be used to create new land. To do this, the project employs a giant barge designed to split open and dump 350 tons of rock in one go.
But adding more rock particles to the water can make it hard for fish to breathe, says Elizabeth Austdal Paulen, Implenia’s environment lead on the project and my fellow passenger on the windy (and soon to be redundant) ferry over to Kvitsøy. Her team monitors their levels in real time: If the particulate count is too high, the drops must pause until the new rock has settled on the seabed. The goal is to protect lobster fishing, a vital part of the local economy, and to safeguard the breeding time for cod, which was an issue when I visited.
Finally, of course, on top of all this are the many hazards for the people who are actually doing all this blasting and digging and hauling. Or, say, for the visitors who are finding their inner nine-year-old getting a little too giddy about what’s next.
Time to blow
Before I’m allowed underground, I must sit through a short safety briefing, where I learn there are multiple hazards when you’re that deep. Fires, for instance, can break out, exacerbated by the way the salt water affects electronics. Just a week earlier, a car caught fire somewhere deep within the network. “You have to be aware all the time,” says Anne Brit Moen, the project lead for Skanska. “It’s a very harsh, harsh climate.”
After the session, I’m given a hi-viz suit, the hard hat (which has built-in ear protectors), gloves, safety glasses, and reinforced boots. I get instructions on how to operate the oxygen mask that will be in the car with me, and a device to put in my pocket that will track my exact location on screens in the control room. The device also acts as a personal warning system: If it vibrates and a blue light appears, then a blast is imminent and I must get to safety; if it vibrates and glows red, umm, well, that’s bad news and it’s time to evacuate.
“If you’re the first to the rescue chamber, press the green button … close the hatch and sit down and be calm.”
Ketil Myklebost, project manager, Implenia
But let’s say I can’t—I’m too deep underground. Then there is a second, less fun option. I’m given instructions on how to access the rescue chambers. These metal boxes—about the size of a large van—can squeeze in around 16 people, and each contains chocolate, water, radio equipment, a defibrillator, and enough oxygen for 24 hours. I see them dotted throughout the tunnels as we drive through. Worst-case scenario, I’m supposed to get to the nearest one, sit tight, and hope to get rescued.
“If you’re the first to the rescue chamber, press the green button for 15 seconds to release pressure,” says Ketil Myklebost, a project manager at Implenia. “And then close the hatch and sit down and be calm.”
Calm, right. Okay.
In the hours before my visit, a huge drilling “jumbo” rig puts as many as 180 holes deep into the rock face. The number, angle, depth, and spacing of the holes is calculated in advance using software but finalized at the face—here, they’re almost six meters deep. At one point, I clamber up into the jumbo and inspect the pattern on its screen, matching it against what I can see on the huge rock face, which stands more than 12 meters tall and wide.
The holes have been stuffed with an explosive slurry. (Someone quips that if I get any on my clothes, I’ll be stopped at the airport as a terrorist. A Norwegian joke, again.) As I watch, workers in a kind of cherry picker fit each hole with a detonator and make sure they’re all connected to one another by wire, ready to be triggered remotely.
Then my personal safety device starts vibrating. When I take it out of my pocket, it’s blinking blue. Showtime.
How far back do I need to be? “It’s dangerous in this direction 500 to 600 meters, but if you’re around the corner you can be closer,” says Sveinung Brude, project manager for the Norwegian Public Roads Administration.
Workers lay asphalt.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
I stand by the worker who will trigger the blast from what looks like a small briefcase with an antenna. Then he presses the button.
The shock wave hits me before I hear it. My chest vibrates. In the first few milliseconds, a propulsive thump briefly stuns my senses, followed immediately by a rolling, crumpled thunder.
Just a moment later—almost instantly, really—wind billows through the cavern. Rocks clatter as they crash off the walls. I try not to show any panic. (That was meant to sound like that, right?) A hush falls, and there’s just the tinkling of stones as they bounce and skip amid the rubble.
Dust rises into the air, and there is a strange smell.
Through my ear protection it sounds like the end of the world.
Niall gets to grips with what it’s like to work under the sea.
NORWEGIAN PUBLIC ROADS ADMINISTRATION
The explosion itself is a beautiful choreography: Blasts are initiated one after another, starting from the center. In video footage, you can just about hear the sequential pitter-patter of the charges as they go off. (In person, it’s a bit more all-at-once and overwhelming.)
Rogfast has just crept another few meters closer to completion.
I find myself grinning. Maybe there’s something extremely primal about being near an explosion? I’m not sure. I look down at my hand, where I have my phone out, recording the intensity of the moment.
Except … I wasn’t recording. The stupid rubber safety gloves I’m wearing must have stopped the command from going through.
Oh no. Oh no.
A once-in-a-lifetime opportunity, and I, uh, blew it. “I WASN’T RECORDING!” I shriek.
“It’s better that way,” says Rønning, walking off into the gloom. “You’ll remember it.” How very Norwegian.
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<![CDATA[Explore how circadian gene rhythms differ in schizophrenia, depression, and bipolar disorder—and why stable sleep timing may curb addiction risk.]]>
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There are plenty of useful things a metric can reveal. There are even more it can obscure or corrupt. It took me well over a decade of tracking my own life in ever greater detail to fully appreciate this duality, which probably reveals something about both me and the nature of measurement.
Like a lot of people bitten by the self-quantifying bug, I initially started gathering personal data to pursue a nebulous collection of goals and desires. As a sedentary technology journalist, I wanted to feel better physically and emotionally, to get outside more, and—where possible—to bring order to some of the messiness and uncertainty of my daily existence. These all seemed to be things that could be improved with the cool clarity of numbers.
Self-quantifiers often get stereotyped as obsessive self-optimizers (and many of them are), but my reasons for producing and collecting personal data were less about life-maxxing and more about life meaning—at least at first. As most people who know me will attest, I do not have now, nor have I ever possessed, a “productivity mindset.” I’m also not all that interested in life hacks, shortcuts, or new ways to compare myself with other people. Instead, what I wanted out of metrics—what I hoped I could divine from a never-ending stream of numbers about my health, work, and social life—was something more elusive: self-knowledge. This was my first mistake.
The idea that the more we know, the better is so profoundly embedded in our culture that it feels weird to even point it out. Since at least as far back as the Enlightenment, the primary way we’ve all agreed to go about knowing more has been through measurement and quantification. After all, more knowledge—more data—leads to better decisions, which leads to happier, more fulfilled people. Or so we’re told, and with increasing frequency in the era of AI.
When two Wired magazine editors, Gary Wolf and Kevin Kelly, coined the term “quantified self” in 2007 and helped launch the movement we are all now helplessly a part of, they were essentially selling this very idea. “Unless something can be measured, it cannot be improved,” wrote Kelly in an early blog post, doing his best impression of Lord Kelvin. “So we are on a quest to collect as many personal tools that will assist us in quantifiable measurement of ourselves.” Almost 20 years later, that quest is easier than ever thanks to a flood of devices, apps, and websites all designed to help us build our self-knowledge through numbers.
My first tool was a small, plastic clip-on Fitbit I started using in 2011. It did one thing: count the number of steps I took in a day. As a lifelong video game player, I was already well acquainted with the motivational power of simple scoring systems, and I hoped my new gadget would offer the gentle numerical nudge I thought I needed to step away from my Twitter feed and, if not touch grass, at least walk next to some. Walking also seemed to be one of the few times I had what could charitably be called intelligent ideas, which seemed like another promising by-product of doing more of it.
Alas, that was short-lived. I can’t tell you precisely when “getting out into nature more” or “thinking smarter thoughts” stopped mattering to me as goals, but I suspect it took no more than a few weeks. What I can say with certainty is that my initial goal of 6,000 daily steps quickly turned into 10,000, which then jumped to 15,000 and eventually settled at 20,000 for years. Stories about becoming a “steps guy” are clichéd at this point, and they’ve earned that status for a reason.
It didn’t take long for me to trade in pedometers for heart-rate monitors (I also started running), smartwatches, sleep-tracking rings, and an embarrassing number of macronutrient-tabulating apps. Outside the health and fitness realm, my early career as a journalist also happened to coincide with the rise of social media and web analytics tools like Chartbeat, which promised to further quantify difficult-to-measure aspects of my life, like “job success” and “impact,” by tracking things like page views, followers, retweets, likes, and all sorts of other attentional metrics that now carry great weight.
Metrics inevitably redefine your core sense of what’s important, whether you’re aware of the trap or not.
Ultimately, during the 10-plus years I diligently tracked my heart rate, steps, active calories, sleep, story engagement time, stress levels, and other metrics, I gained virtually nothing in terms of greater self-knowledge. (I suppose I did learn that I liked to make numbers go up and down, but who doesn’t?) The swirl of data that followed me everywhere did not lend additional meaning or insight to the way I relate to myself, my work, or the important people in my life. In fact, the more I used numerical proxies, the worse I felt about pretty much everything.
What I did learn were two important lessons about what happens when you try to quantify the minutiae of your life. First and foremost, whatever the amount of data you’re currently collecting about yourself, it will never feel sufficient. There’s always a new metric around the corner, a better way for a tracker to remix its readings and more accurately measure what’s “important”: heart rate variability, daily stress, exercise “readiness,” cardiovascular or “fitness” ages. Measurement begets more measurement. You can count on it.
The Score: How to Stop Playing Somebody Else’s Game C. Thi Nguyen
PENGUIN PRESS, 2026
The second lesson was less obvious but no less significant. The more personal or nuanced your goals are when you set off on your self-quantifying journey, the more likely it is you will ultimately replace them with some simplified metric or ranking. Want to become a better journalist? Why not use page views and leaderboards as a proxy for success? Enjoy cooking and want to improve? Foodie metrics dictate that more complicated recipes with longer ingredient lists are the answer. Even when we know that the value of good journalism isn’t reflected in how many people read a given story or that the joys of cooking are as much about improvisation and experimentation as about successfully following some complex recipe, it’s hard to resist the allure of a simple score or stat. Metrics inevitably redefine your core sense of what’s important, whether you’re aware of the trap or not.
Over the years, people have invented various terms to describe this phenomenon. In his recent book The Score: How to Stop Playing Somebody Else’s Game, the philosopher C. Thi Nguyen calls it “value capture.” Value capture happens, he says, when you adopt external sources of measurement and then let them rule you without adapting them to suit your life. “In value capture, you’re essentially outsourcing your values,” Nguyen writes. “You’re letting an external metric or ranking set what’s important for you.” Crucially, you’re also outsourcing the process of figuring out your own sense of meaning. It’s why my walks quickly shifted from feeling meditative to prioritizing miles.
Individuals, institutions, and indeed entire societies can fall prey to value capture. In fact, once you start noticing it, you start seeing it everywhere—in journalism, education, and business, but also in our food, our hobbies, and, yes, the way we measure our health and happiness. Here’s how Nguyen puts it:
Value capture happens when a restaurant stops caring about making good food and starts caring about maximizing its Yelp ratings. It happens when students stop caring about education and start caring about their GPA. It happens when scientists stop caring about finding truth and start caring about getting the biggest grants. It even happens in religion. A pastor recently told me that his church had become completely obsessed with baptism rates. The higher-ups had established an internal leaderboard in which the pastors competed on monthly baptism rates, and it was starting to dominate everybody’s attention. He’d found himself caring less about the long-term spiritual development of his flock and focusing more on trying to deliver popular sermons that would up his baptism rates and move him up that leaderboard.
At its core, The Score is trying to untangle a mystery that Nguyen, a specialist in the philosophy of games at the University of Utah, has been thinking about for a long time: Why is it that numbers and scoring systems in games can be the source of so much joy and fluidity and play, but public measures and institutional metrics (i.e., scores that apply to the real world) seem to drain the life out of everything and thrust us all into a bleak mindset of grinding optimization?
Porter, a historian of science who specializes in the social power of numbers, has spent his career looking at why quantification has become so dominant, not just in political and bureaucratic life but everywhere. One of his key insights about the inherent attractiveness of quantification, which he calls “a technology of distance,” is that it “minimizes the need for intimate knowledge and personal trust.” Put another way, metrics travel extremely well between different contexts and are easy to grasp and aggregate.
Whether it’s a student’s GPA or a country’s GDP, these measures are understood by pretty much everyone. But that understanding comes at a price, Porter reminds us: To arrive at a clear metric, you inevitably need to simplify what you’re attempting to measure, often jettisoning heaps of nuanced, qualitative, or open-ended information so that others can find the resulting number legible.
No one (hopefully) believes that a GPA captures in any meaningful way a student’s entire educational experience or aptitude for learning, but we’ve agreed to use it because more qualitative assessments are onerous to wade through and require expertise to decipher and compare. Ditto for the economic metric of GDP, which politicians and societies are now compelled to drive higher and higher because a group of economists once concluded that this figure correlates with general economic well-being.
This is the essential tension at the heart of all data, argues Nguyen. Any institutional quantification, he says, requires that the evaluation procedure and its product be comprehensible across contexts. That profoundly limits what the metric can actually measure. “In value capture, you’re ultimately taking that decontextualized nugget and internalizing it,” he writes. “You’re guiding your life using an evaluative technology that has been engineered to travel between contexts, by stripping it of nuance.”
Every so often I’ll find myself in friendly debate with a “numbers person”—a statistician, an economist, or a friend who’s still a committed self-quantifier. After patiently listening to my measurement-gone-awry examples—the disastrous attempt to quantify pain as “the fifth vital sign” in the mid-1990s (which exacerbated the opioid epidemic), or any of the countless examples of the McNamara fallacy, where decisions in academia, medicine, and politics are based solely on what’s easily measured—many will insist that I’m misunderstanding or misinterpreting the whole point of measuring. Metrics, they’ll say, are simply a means, and the important questions concern the ends for which they are used. In other words, these unfortunate outcomes amount to user error, not something inherently dangerous or misleading about the nature of measurement.
At some point during these conversations, Goodhart’s Law will invariably come up, usually as an explanation the metrics-minded deploy for why the ends get all mucked up. The principle, which is attributed to the British economist Charles Goodhart, is often expressed as the following: “When a measure becomes a target, it ceases to be a good measure.” I have a profound dislike for Goodhart’s Law, not because I think it’s untrue, but rather for the way it gets interpreted.
As Nguyen notes, Goodhart’s Law says very little about why metrics fail to capture what’s important—or what to do about it. Find better measures, some will conclude. Don’t let metrics become targets, others will insist. These are not helpful takeaways. All measurements, I would argue, are in fact targets, whether you intend them to be or not. Metrics inevitably present one direction or option as better, Nguyen writes in The Score—“longer lifespans, faster student graduation rates, more page views, higher customer satisfaction scores.” What people are talking about when they bring up Goodhart’s Law isn’t human error; it’s actually a fundamental problem with measurement itself.
I want to be clear here: Measurement can and does serve a number of vital functions. It has in a very literal sense made the modern world possible, with all its life-saving, suffering-reducing, and awe- inspiring scientific breakthroughs. When used with care and diligence, metrics can make our progress (or lack of it) clearer and more transparent. Are we decreasing carbon dioxide emissions or not? They can also introduce accountability into formerly opaque systems, such as by measuring whether a company is complying with state and federal regulations. They can even make us more objective, reduce biases, and galvanize us to act.
But as Nguyen points out throughout The Score, the fundamental weakness of metrics comes when we use them to pursue subtler, more personal goals. What I think many of us miss—what I know I certainly missed—is that there are always trade-offs when you try to distill something important down to a data point. When we turn to metrics to understand ourselves, our social world, and culture as a whole, they will never come close to capturing what matters. Even worse, they’ll often actively obscure it.
Today, I find that numbers have very little to offer when it comes to my daily work, my physical or mental fitness, my relationships, or any other part of my life I consider important. Granted, I’m lucky enough to be in relatively good health at the moment. I don’t have to track my glucose levels or monitor my blood pressure. As a freelance writer, I also have the luxury of not having numbers foisted on me in the form of key performance indicators (KPIs), objectives and key results (OKRs), or any of the endless quantitative evaluations that come baked into pretty much every corporate and gig economy job.
Still, in a very real sense, there is no escaping metrics or, especially, the logic that accompanies them. Knowing has become numeric, and we all live in a world that increasingly sees us as a collection of numbers—as “data subjects.” The first and most urgent challenge, I’d suggest, is finding a way to keep us from seeing ourselves and each other that way.
This won’t be easy. As Porter, Nguyen, and countless other philosophers, anthropologists, and historians have already observed, the language of numbers is largely how we ascribe value today—as well as how we digest and metabolize our relationships to ourselves, to others, and to the world around us. Indeed, many of us have accepted not only that metrics have a natural existence in human affairs but that there are in fact no aspects of human life that cannot be somehow translated into data.
Knowing has become numeric, and we all live in a world that increasingly sees us as a collection of numbers— as “data subjects.”
So how do we push back? Nguyen’s book offers a useful first step. As he notes again and again in The Score, believing that numbers say something real or useful about human needs and desires gives them power. We can, at the very least, start to seriously question that belief, to ask what meaning and pleasure we might be giving up in pursuit of a metric.
Doing so will hopefully lead to another realization: that playing the numbers game is ultimately a losing proposition for humans. If we insist on expressing our worth through attentional metrics and productivity scores, if we continue to turn intelligence and creativity into a series of benchmarks for AI to surpass, we’ve already lost. Of course machines will surpass us in a world built around metrics. That is literally what we create them to do. The answer is not to turn ourselves into machines too.
If there’s one thing that keeps me up at night, it is that we’ve become so accustomed to seeing and understanding the larger world and ourselves through numbers that it has deprived us of the language to express what’s fundamental and valuable about our own humanity. We need this ability now more than ever, especially if we’re going to adequately answer two of the most important questions of our era: What are humans for? And what is AI for?
As part of my own attempts to disentangle myself from a life of numbers—efforts that started shortly before covid—I’ve abandoned most of the tools of measurement I spent a decade collecting. I’ve largely given up on social media. I stopped using apps to track my health and well-being. The watch I currently wear tells me the time and the date and nothing else.
In fact, the only holdover from my days of obsessive self-quantification is a dogmatic devotion to walking—without all the step counting, of course. These days, I walk when I’m feeling disillusioned or overwhelmed; I walk when I can’t figure out how to finish an essay; I also walk because I enjoy spending time outdoors with my dog and catching up on the details of my neighbors’ lives. The benefits of pursuing this daily activity are as clear and obvious to me as anything could be in life. I just can’t express them in a number.
Bryan Gardiner is a writer based in Oakland, California.
Cao et al. identify tryptamine as a sleep signal in mice. Wake-active monoaminergic neurons release tryptamine, which binds to GPR139 in POA neurons that suppress wake-promoting neurons. GPR139 agonists could be a new class of sleep medication.
