72×72 no longer a shrug: tracking your brain

track your – A simple mental maths moment becomes the doorway to a bigger shift: researchers and clinicians are moving toward ways to monitor brain health like physical health—using blood tests, scans, sleep patterns, heart-rate variability, and emerging composite scores.

When 72 × 72 flashed up from the back seat, I didn’t just stumble—I stalled. It was the kind of problem that should come easily, mental maths I’ve handled without thinking. But lately my brain has felt slow in a broader, more uncomfortable way. Not just numbers. General sluggishness. The fear isn’t dramatic enough to name, but it’s there.

I’m a brain writer, and I still try—carefully, consistently. I eat well, exercise, and even play the trumpet. It all feels like it should count. Yet brain health is stubbornly hard to monitor. There’s no waistline to measure. no blood pressure cuff that tells you how the day is going inside your skull.

That, neurologist Hedley Emsley at Lancaster University in the UK argues, is starting to change. “I think we’re probably at the beginning of a shift toward treating brain health more like physical health – something we monitor proactively rather than reactively. ” he says. And behind that shift is a growing belief that technology and data—sometimes powered by artificial intelligence—could turn vague concerns into something you can track.

The marketplace is moving fast, and so is the research culture around brain health. In the early 2000s. few people talked about it; neuroscience was more focused on what makes a brain ill than on defining what makes one thrive. Around that time, the number of studies referring to brain health could be counted on both hands. Now, more than 4000 studies are published on the topic each year.

One reason is cultural. People track steps, sleep, and heart rate; the brain feels like the next measurable thing. Unease over mental health may have pushed that interest as well. In a survey of US adults by Muse. a neuro-wearables company. around 40 per cent said they have an undiagnosed brain condition. with anxiety and depression topping the list of concerns. Given the chance. most said they would take a brain health test—even if it produced information about a disease that can’t be treated or prevented.

There’s also the technology side. Non-invasive EEG devices are cheaper than ever. and AI can now analyse. interpret and personalise brain-imaging data in real time—improvements that. just five years ago. would have been out of reach. The result is a fast-growing set of tools promising insight into what’s happening between our ears. and whether the brain looks healthy for your age.

I decide to start with something I already know about: my genes.

More than a decade ago. I had my DNA analysed and discovered I carry one copy of the APOE4 gene variant. People without that variant are. on average. less likely to develop Alzheimer’s disease; with APOE4. the likelihood is increased by three to four times. I can find tests that tell you whether you have this variant—but whether you want that information is another story.

Even my result doesn’t give me a picture of how my brain is doing right now. It also doesn’t mean Alzheimer’s is inevitable. Alzheimer’s organisations in the UK and US don’t recommend these tests. Their position is that lifestyle factors weigh heavily on ultimate risk.

So I consider the other kind of evidence: seeing the brain.

A brain scan can reveal bleeding. tumours. shrinkage. vascular damage and other age-related changes that might offer insight into current—and future—brain health. I already have a picture stored safely on my computer from a clinical trial I took part in. and it looks beautiful. In my case, the scan didn’t pick up any unexpected anomalies known as incidental findings.

But that’s not how it goes for everyone.

Rab Khan. a stroke physician at the Northern Care Alliance NHS Foundation Trust in Manchester. UK. says incidental findings show up in around 4 per cent of all brain scans. Some findings—like small cysts or unusual blood vessel growth—won’t cause harm or explain symptoms. Others can trigger anxiety, more scans, and expense. Khan is clear: none of the doctors he spoke to recommends routine brain scans. “Yearly or every-few-years scanning sounds proactive, but it is not supported as a general brain health strategy,” he says.

I decide against another scan.

Blood tests, then.

Simple checks of vitamin B12. folate and thyroid function can be revealing. because deficiencies and hormone imbalances can cause memory loss and cognitive impairment. As part of a “Well Woman” package. my latest test didn’t flag anything out of the ordinary—at least. so far. my brain seems to be doing OK on those basics.

But even here, the limits are obvious. These tests are blunt. And increasingly, more specialised options exist.

Alzheimer’s blood tests can detect levels of beta-amyloid and tau—two proteins that contribute to the destruction of brain tissue in Alzheimer’s disease. Some of these tests can outperform brain scans in certain cases by spotting tell-tale signs of disease well before symptoms occur. That promise comes with a catch. Although such tests are available privately. they aren’t generally recommended for people without symptoms. because their predictive value is still being investigated and treatment options remain limited.

Other experimental blood tests aim to detect inflammation in the brain.

Evgeniia Lobanova at the University of Cambridge and her colleagues are studying protein clumps called specks. released by the brain’s immune cells when they spot trouble. The specks appear to drive inflammation and cell death. Their shape and size may help distinguish people likely to develop Parkinson’s disease or Alzheimer’s up to five years before symptoms show. “With this test. I can look at a patient’s blood and identify those who will very much benefit from being on a drug trial. ” Lobanova says.

For now, this is still a way off from routine clinic use.

If someone has serious concerns about their brain function, the near-term path is more conventional. You can ask a family doctor for an assessment. which can flag problems with memory. concentration and awareness of time and place. Online tests also exist, measuring everything from reaction speed to executive function. But many of them are designed to detect impairment. What if you aren’t trying to find or eliminate a specific disease—what if you just want to know whether your brain is in good shape?.

That question takes me to a newer idea: your body might already be carrying the clue, passively.

Emsley says researchers are increasingly interested in passive behavioural signals—data from other areas of the body that can reflect brain activity. I wear a smart watch that tracks my sleep, physical activity and heart rate to monitor my physical health. More researchers now believe these kinds of data might offer insight into brain health, too.

Sleep is a clear place to start. It’s not just restorative; it’s a highly organised state in which synchronised neural rhythms help drive waste clearance from the brain via the glymphatic system. Bad sleep, in the long term, may impair the removal of things like beta-amyloid and tau. Maiken Nedergaard at the University of Rochester Medicine in New York state says: “Many disorders that increase dementia risk also disrupt the brain’s sleep rhythms.”.

The science used to require a sleep lab overnight to glimpse the brain’s rhythms. Now, researchers point to a proxy that can be measured more easily.

Heart rate variability (HRV)—tiny variations in time between heartbeats—has been linked to several cognitive and mental health conditions. Low HRV is linked to a higher likelihood of depression, and it has also been connected to dementia, schizophrenia and post-traumatic stress disorder.

Nedergaard says her recent study with colleagues may provide the link between heart rate dynamics and brain health. The work suggests that the pumps driving glymphatic clearance are driven by the same mechanisms that drive HRV during sleep. She speculates that HRV could be used as a biomarker for how well the brain is clearing debris. The idea hasn’t yet been directly tested. but the literature shows low HRV predicts less favourable ageing. including an increased risk of dementia.

My own HRV has always been lower than average, which suggests I spend more time in a fight-or-flight state. I already use it as a nudge to be kinder to myself, doing things that help me de-stress. Learning it might also reflect the brain’s waste disposal system being compromised pushes that habit into sharper focus—even if the evidence is still preliminary.

Still, Emsley warns that the signals are not simple. “The challenge is that the brain is far more complex and variable than something like heart rate. so I suspect the future will be less about a single ‘brain score’ and more about combining multiple signals over time to detect meaningful changes early – ideally in ways that are actionable rather than anxiety-inducing. ” he says.

The need to avoid a single number that people cling to is one reason researchers are exploring how to combine signals.

Some have even tried to build a single test.

One approach from 2018 attempted to combine four different MRI brain scans—each sensitive to separate brain problems such as lesions, atrophy or white matter changes reflecting tissue damage—and boil them down into one number: the brain health index (BHI).

David Dickie at the University of Glasgow. UK. and his colleagues showed that a person’s BHI ties more closely to reaction times. used as a proxy for healthy ageing. and to cognition assessment scores than to individual tests of brain atrophy and disease alone. In 2023. a study led by Jodi Watt—also at the University of Glasgow—identified the BHI of almost 3000 people aged between 48 and 77 and derived a “normal” BHI curve for different ages. Watt and her colleagues later showed that BHI reflects factors known to influence brain health. Education seemed to improve it. Smoking, type 2 diabetes and hypertension all worsened it.

The tool still needs refining, but the appeal is plain: poor brain health is rarely caused by a single pathology. Combining multiple pieces into one score may offer a better snapshot of how your brain health compares with what’s typical.

But I’m wary of anything that only shines a light on what’s wrong. I’m trying to do things that help. I want to see effort rewarded—muscles growing, cholesterol dropping—rather than a score that only tells me what I’ve already lost.

That’s where lifestyle-focused dementia prevention starts to loom large.

In 2024, the Lancet Commission on Dementia Prevention, Intervention and Care showed that almost half of all dementia cases could be prevented or delayed by addressing 14 lifestyle factors. Those include smoking, diabetes, physical activity, social isolation and hearing loss.

For Christin Glorioso, founder of NeuroAge Therapeutics, the report landed personally. A neuroscientist with a family history of Alzheimer’s and, like me, one copy of APOE4, she wanted not just to understand what helps but to track it.

Her team had already shown that some people’s brains are biologically older or younger than their chronological age. based on patterns of gene activity in brain tissue. People with brain age older than their chronological years were more likely to get Alzheimer’s or experience cognitive decline. Crucially. they found that having a brain age five years younger than your actual age could offset the impact of having one copy of APOE4.

“So I thought, ‘OK, if the goal is to be minus five years, how do I track how old my brain is, and what’s working?’” Glorioso says. “And that’s how we came up with the NeuroAge test.”

NeuroAge costs $1398 for the full package, which includes an MRI, genetic analysis, cognitive assessments and a consultation. I don’t want to pay that. But the cognitive assessment component is available for $9.99 a month. offering a rough estimate of brain age using tests of memory. attention. visuospatial performance and processing speed.

There are limitations. In my case, the cognitive testing found my brain age was 21 years younger than my real age. I suspect this reflects my knowledge of memory tricks. Glorioso points out that my reaction times were also youthful, so maybe my brain is healthier than I think. Either way, she argues that the key value may be tracking change over time rather than obsessing over the number.

I can see the appeal, but I’m not sure I want to pay hundreds of dollars over the years.

What does feel important is the message embedded in the science: even as people approach middle age. it may not be too late to wind back brain age. Lori Cook at the University of Texas at Dallas puts it plainly: “Brain health isn’t just trying to stay on top of decline or disease. it’s about asking yourself ‘How can I make next year my best brain health year yet?’” She adds: “You need to recognise that potential for optimisation. that you can improve your brain health on an upward trajectory. no matter where you start.”.

To turn that optimism into measurement, Cook and her colleagues launched the BrainHealth Project in 2020. The aim is to create a more holistic measure of brain health that can track improvements and identify what works. The study plans to enrol up to 100. 000 people over 10 years. collecting cognitive data through brain games along with lifestyle information and metrics such as HRV.

Cook says the brain health definition cannot be limited to reaction times and memory. It also draws on the World Health Organization’s definition of brain health, including social and emotional factors—how socially connected you are, how you manage stress, and what activities you engage with.

Participants provide data every six months. They receive a composite score. but the point isn’t to compare people with “normal.” “The score doesn’t define “normal” ranges because its purpose is not to compare people or groups. ” Cook says. “It shows how an individual’s brain health can change and improve over time – it’s you against you.”.

Around 40,000 people have already signed up. Early findings show how interlinked factors can be: sleep appears highly supportive for cognitive growth. and compassion seems to have a positive effect on cognition as well as wellbeing. Multitasking, by contrast, seems toxic. Cook says: “We think that constantly switching between things leads to chronic stress. which hinders neural function and impacts emotional regulation.” So. no more mental maths while parking for me.

The messy reality is that there isn’t yet a single perfect way to assess brain health. But over time, individual tests can build a pattern—one that suggests whether your brain health is moving upward or drifting downward.

By that logic, I’ll keep my focus on the things that are easiest to measure and repeat: sleep, HRV and social connections. Every six months, I’ll check in with the BrainHealth app. Together, they should show whether the changes I’m making are nudging my brain health in the right direction.

And next time a calculation like 72 × 72 comes flying at me from the back seat, I won’t just guess. I’ll have a better sense—measured, tracked, and hopefully earned—of how my brain is doing.

brain health Alzheimer’s APOE4 blood tests MRI incidental findings HRV sleep glymphatic system brain health index BrainHealth Project dementia prevention NeuroAge test