What is brain health? Ask ten people, and you’ll likely get ten different answers. Is it memory? Mental sharpness? Freedom from dementia? The absence of disease?
Now compare this to cardiovascular health. We have clear metrics, known risk factors, wearable trackers, and standardized ways to improve it. Brain health, conversely, is difficult to define or improve intentionally.
This is beginning to change. The scientific community and public health policymakers are making rapid progress in defining what brain health truly means – how to measure it, what influences it, and, most importantly, how we can improve it throughout life.
What you’ll learn in this article is that brain health is not only measurable, but also changeable throughout our lifespan. The emerging picture is a more hopeful one than most people realize.
Defining Brain Health
In 2022, the World Health Organization (WHO) finally offered a comprehensive definition of brain health.
They describe it as “the state of brain functioning across cognitive, sensory, social-emotional, behavioral, and motor domains, allowing a person to realize their full potential over the life course, irrespective of the presence or absence of disorders” (WHO, 2022).
It can be objectively measured and subjectively experienced. It's influenced by a wide array of factors – a complex interplay between biology, psychology, social factors, and environment.
“Irrespective of the presence or absence of disorders"
That last component of the WHO definition – “irrespective of the presence or absence of disorders" – is key.
Brain health isn't simply the absence of disease. Someone can have a neurological condition and still optimize their brain function.
Conversely, someone without any diagnosed disorder might have poor brain health due to chronic stress, poor sleep, social isolation, or other factors that degrade cognitive and emotional functioning.
For decades, neurology focused primarily on pathology – diagnosing and treating diseases. So this marks a departure from that characterization.
Brain health under this modern definition takes a broader view. It relates to physical and mental health, social well-being, productivity, and creativity.
Why Brain Health Matters So Much Now
Neurological conditions are the leading cause of disability worldwide, affecting over 1 in 3 people (Livingston et al., 2024). Stroke, Parkinson's disease, multiple sclerosis, traumatic brain injury, depression, anxiety, and dementia all fall under this umbrella.
Around 55 million people worldwide currently live with dementia, projected to reach 152 million by 2050. The economic burden already exceeds $1.3 trillion annually for dementia alone.
However, this is no foregone conclusion. Increasingly, we're discovering that brain health is far more malleable than we thought.
The Lancet Commission identified 14 specific modifiable risk factors that, if addressed throughout life, could prevent or delay nearly half of all dementia cases (Livingston et al., 2024).
These include less education in early life, high blood pressure and obesity in midlife, and factors like physical inactivity, smoking, depression, social isolation, diabetes, excessive alcohol consumption, hearing loss, traumatic brain injury, air pollution, vision loss, and high cholesterol across the lifespan.
Some of these – such as education and early childhood experiences – are influenced by factors beyond our individual control, underscoring the importance of societal action.
Others – like exercise, diet, and social connection – are areas where personal choices accumulate over time.
The Four Domains of Brain Health
Researchers have similarly defined brain health as a lifelong, multidimensional, dynamic state comprising cognitive, emotional, sensory, and motor domains, all underpinned by physiological processes (Chen et al., 2021).
Let’s take a closer look at the four key domains identified:
1. The Cognitive Domain
Every time you focus on a complex task, recall where you left your keys, or solve a problem at work or in your personal life, you're drawing on cognitive health.
Cognitive performance is built in layers. Basic processes like sensing and perceiving form the foundation, while higher-level functions such as decision-making and self-control sit on that foundation. These levels work together, with each component influencing and supporting the others. (Harvey, 2019).
2. The Emotional Domain
The emotional domain governs mood regulation, stress response, motivation, and your capacity for emotional connection.
This is about whether you can manage frustration without spiraling, experience joy and satisfaction, regulate anxiety, and maintain emotional stability. Depression, chronic stress, and emotional dysregulation all reflect your state of brain health in this domain.
3. The Sensory Domain
The sensory domain covers how you perceive the world – vision, hearing, touch, balance, taste, and smell. Your brain actively processes sensory information to understand your environment, communicate, and engage with the world around you.
Sensory function directly affects cognitive load, social interaction, and your ability to learn from your surroundings.
4. The Motor Domain
The motor domain is one of the most overlooked areas in brain health. Your brain controls every movement, from the fine motor control needed to type to the complex coordination required for balance and gait.
Motor abilities include fine motor skills such as manual dexterity and motor speed, as well as reaction time and more global skills such as balance. Even subtle changes in coordination, balance, or movement fluidity can signal declining brain health.
What Influences Brain Health Across Our Lifespan
Brain health is primarily influenced by your physical health, environment, social and economic stability, and access to healthcare. Genetic risk matters, but it’s not an absolute destiny.
Take Alzheimer's as an example. It does carry a heritability of roughly 60–80% in some studies (Gatz et al., 1997; Rousset et al., 2024). The APOE-ε4 gene is the most substantial risk factor, with one copy increasing risk 3–4 fold and two copies increasing risk 8–12 fold (Belloy et al., 2019).
However, a major study published in The Lancet found that 45% of Alzheimer’s cases are still preventable with interventions throughout our lifespan (Livingston et al., 2024).
Think of it as decades of cumulative lifestyle factors – some we can control, some we can’t – meeting genetic biology.
Your brain at 70 reflects what happened at 50, 60, and beyond. Uncontrolled negative lifestyle factors at 50 – such as a poor diet, poor sleep, or chronic stress – may increase the odds of cognitive decline later in life.
Critically, however, the flip side is equally true. Positive lifestyle changes can sway, even defy, the weight of probability.
The Five Key Determinants Of Brain Health Across Our Lifespan
No single factor defines brain health. It develops over decades through interactions with the air you breathe, the relationships you maintain, how well you sleep, diet and exercise, social connections, and more.
The key is that many of the forces pushing the brain health in one direction or another aren’t fixed. They can be steered towards positive outcomes.
Below, we break down five key determinants of brain health backed by research.
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What Influences Brain Health |
Why It Matters |
What You Can Do |
|
Physical Health |
Your brain is metabolically and nutritionally demanding and relies on a healthy body to function well. Cardiovascular disease, diabetes, chronic inflammation, and obesity all disrupt the blood flow, oxygen delivery, and nutrient balance your brain needs to work effectively. What benefits your cardiovascular health tends to protect your brain, too. |
Support your metabolic and vascular health through consistent physical activity, balanced nutrition, quality sleep, and managing your blood pressure, glucose, and weight. Even modest improvements – like adding a regular walk to your day or establishing a better sleep routine – can yield measurable brain benefits. |
|
Environment |
Your surroundings positively and negatively influence your cognitive health over time. For example, exposure to air pollution is now recognized as a neurological risk factor, while access to education, stimulating work, safe water, and clean air all support better outcomes for your brain (Ebong et al., 2024). |
Reduce your exposure to air pollution where possible – indoor air filtration, avoiding heavy-traffic routes during peak hours. Seek out cognitively stimulating environments, and advocate for community-level improvements in air quality and educational access. |
|
Safety & Security |
Persistent stress from violence, instability, or socioeconomic hardship can alter your brain's structure and function (Merz et al., 2019; Saxbe et al., 2020). Environments that promote safety help your brain allocate resources toward learning and adaptation rather than constant threat response, which benefits your overall brain health. |
Build supportive routines and stress-buffering habits into your life – mindfulness practices, regular exercise, connecting with community resources, or seeking counseling where available. Policies that reduce insecurity and violence also protect brain health at the population level. |
|
Social Connection |
Regular, meaningful interaction helps preserve your cognitive function. Loneliness and isolation are associated with increased risk for cognitive decline and neurodegenerative disease, comparable to traditional medical risk factors like hypertension. Social connection acts as a buffer against stress and supports your mental resilience. |
Maintain and prioritize your social interactions – through friends, family, volunteering, or community groups. Even small, consistent contact like weekly phone calls or shared activities helps sustain your cognitive and emotional health over time. |
|
Ongoing Monitoring |
Many conditions that undermine brain health are modifiable if you can identify and manage them early. Uncontrolled hypertension, diabetes, and hearing loss can silently erode your cognitive function over decades. Preventive care and routine monitoring help you maintain brain health over the long term. |
Stay engaged in preventive care where you can – periodic checkups, hearing and eye tests, and regular monitoring of your vitamin, mineral, blood pressure, and glucose levels. Small, active interventions can slow or prevent many forms of cognitive decline. |
Taken together, these five determinants form the foundation of long-term brain health.
None operates in isolation; they interact, reinforce one another, and compound over time. Improvements in one area often strengthen the others, while neglect in any single domain can quietly undermine the whole system.
The goal is not necessarily perfection, but steady alignment toward conditions that allow the brain to function, adapt, and age well.
Where to Start
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Sleep consistency: Aim for regular bed and wake times to support memory consolidation and overnight waste clearance.
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Daily movement: Prioritize moderate physical activity, such as walking, cycling, or swimming, most days of the week.
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Social touchpoints: Schedule recurring time with friends, family, or community groups to reinforce emotional resilience.
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Basic health monitoring: Stay current on blood pressure, glucose, cholesterol, hearing, and vision checks.
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Mental engagement: Commit to ongoing learning through reading, courses, puzzles, or skill development.
- Dietary upgrades: Emphasize whole foods and reduce reliance on ultra-processed options.
Brain Health Is a Lifelong Investment
For much of modern medicine, brain health was defined primarily in terms of disease and decline. Today, that understanding is expanding.
We now know that brain health is measurable, multidimensional, and shaped by our biology, environment, relationships, and daily habits.
Strong evidence shows that a substantial portion of cognitive decline can be prevented or delayed. Education, movement, sleep, nutrition, stress management, social connection, and early detection are not secondary concerns – they're central to long-term cognitive resilience.
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References
Chen, Y., Demnitz, N., Yamamoto, S., Yaffe, K., Lawlor, B., & Leroi, I. (2021). Defining brain health: A concept analysis. International Journal of Geriatric Psychiatry, 36(12), 1891–1903. https://doi.org/10.1002/gps.5564
Ebong, I.A., Goff, D.C., Rodriguez, C.J., Chen, H., & Bertoni, A.G. (2024). Maintenance of brain health: The role of social determinants of health and other non-traditional cardiovascular risks. Cerebral Circulation - Cognition and Behavior, 6, 100213. https://doi.org/10.1016/j.cccb.2024.100213
Gatz, M., Pedersen, N.L., Berg, S., Johansson, B., Johansson, K., Mortimer, J.A., Posner, S.F., Viitanen, M., Winblad, B., & Ahlbom, A. (1997). Heritability for Alzheimer's disease: The study of dementia in Swedish twins. The Journals of Gerontology: Series A, 52A(2), M117–M125. https://doi.org/10.1093/gerona/52A.2.M117
Harvey, P.D. (2019). Domains of cognition and their assessment. Dialogues in Clinical Neuroscience, 21(3), 227–237. https://doi.org/10.31887/DCNS.2019.21.3/pharvey
Livingston, G., Huntley, J., Liu, K.Y., Costafreda, S.G., Selbæk, G., Alladi, S., Ames, D., Banerjee, S., Burns, A., Brayne, C., Fox, N.C., Ferri, C.P., Gitlin, L.N., Howard, R., Kales, H.C., Kivimäki, M., Larson, E.B., Nakasujja, N., Rockwood, K., Samus, Q., Shirai, K., Singh-Manoux, A., Schneider, L.S., Walsh, S., Yao, Y., Sommerlad, A., & Mukadam, N. (2024). Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. The Lancet, 404(10452), 572–628. https://doi.org/10.1016/S0140-6736(24)01296-0
Merz, E.C., Desai, P.M., Maskus, E.A., Melvin, S.A., Rehman, R., Torres, S.D., Meyer, J., He, X., & Noble, K.G. (2019). Socioeconomic disparities in chronic physiologic stress are associated with brain structure in children. Biological Psychiatry, 86(12), 921–929. https://doi.org/10.1016/j.biopsych.2019.05.024
Rousset, R.Z., den Braber, A., Verberk, I.M.W., Boonkamp, L., Wilson, D.H., Ligthart, L., Teunissen, C.E., & de Geus, E.J.C. (2025). Heritability of Alzheimer's disease plasma biomarkers: A nuclear twin family design. Alzheimer's & Dementia, 21(1), e14269. https://doi.org/10.1002/alz.14269
Saxbe, D., Khoddam, H., Piero, L.D., Stoycos, S.A., Gimbel, S.I., Margolin, G., & Kaplan, J.T. (2020). Socioeconomic disadvantage, chronic stress, and hippocampal subfield development in children. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, 5(11), 1009–1018. https://doi.org/10.1016/j.bpsc.2020.06.015
World Health Organization. (2022). Optimizing brain health across the life course: WHO position paper. World Health Organization. https://www.who.int/publications/i/item/9789240054561
