The Connected Body
What heart health, brain health, and living systems teach us about designing for intelligence
For a long time, medicine treated the body as a set of separate parts.
Cardiologists focused on the heart. Neurologists studied the brain. Endocrinologists looked at hormones. Each system had its own specialists, measurements, and treatments.
But biology has never really worked that way. Living systems are integrated. Circulation influences cognition. Sleep affects metabolism. The immune system shapes brain function. When one part of the system weakens, the effects ripple outward.
One of the most interesting examples of this integration is the relationship between the heart and the brain.
At first glance, they seem like very different organs. One pumps blood; the other generates thought. But in reality, they depend deeply on one another.
Your brain accounts for only about 2% of your body weight, yet it uses roughly 20% of the blood your heart pumps.[1] Every thought, memory, and decision depends on a vast network of blood vessels delivering oxygen and nutrients to billions of neurones.
Protect those vessels, and you support the brain. Damage them, and cognition itself can suffer.
This idea — that the health of the brain depends on the health of the body’s infrastructure — is becoming increasingly clear in modern research.
But it is also something nature has always known.
A systems lesson from biology
One of the first lessons in biomimicry is that nature rarely designs isolated solutions. Instead, biological systems evolve to support whole-organism resilience. Circulation, metabolism, immunity, and cognition are not independent modules. They are deeply interconnected processes that help an organism survive in its environment.
In many ways, the human body behaves less like a machine and more like an ecosystem. Energy flows. Signals travel. Resources move through networks. The stability of the system depends on the health of its connections.
When researchers study the link between cardiovascular health and cognitive decline, they are essentially rediscovering this systems principle.
Damage to blood vessels — through inflammation, pollution exposure, poor sleep, or metabolic stress — can disrupt the delicate network that nourishes the brain. And when that network degrades, cognition can degrade as well.
The infrastructure of thinking
We often imagine thinking as something that happens purely inside the brain. But biological intelligence depends on infrastructure.
Neurones require a constant supply of oxygen and glucose. Waste products must be cleared away. Temperature, sleep cycles, and immune signals all influence how well the brain functions.
If this support system falters, the brain struggles to operate effectively.
This insight mirrors something researchers increasingly recognise in artificial intelligence.
Large AI systems are often described in terms of algorithms and models. But their capabilities depend heavily on physical infrastructure — energy supply, cooling systems, specialised chips, and data networks. Without those supporting systems, the intelligence simply cannot run.
Biological cognition works similarly. The brain does not think in isolation. It thinks as part of a living system.
The two biological processes shaping both heart and brain
Many different stressors affect human health, but they often converge through two common pathways.
Chronic inflammation
Inflammation is the body’s natural repair response. In the short term, it protects us from injury and infection.
But when inflammation becomes persistent — triggered by stress, pollution, poor diet, or disrupted sleep — it begins to damage tissues.[2] Over time, this low-grade inflammation can injure the lining of blood vessels, accelerate plaque formation in arteries, and affect the brain’s protective barriers.
Markers of inflammation associated with cardiovascular disease are also frequently elevated in people experiencing cognitive decline.[3] The same process is affecting multiple systems at once.
Oxidative stress
Another shared pathway is oxidative stress.
Every cell produces unstable molecules called free radicals as part of normal metabolism. Under healthy conditions, the body neutralises them with antioxidants.
But environmental pollutants, ultraviolet radiation, psychological stress, and metabolic strain can tip the balance.
When this happens, oxidative stress damages cells, blood vessels, and mitochondria — the energy systems inside cells.
Both cardiovascular disease and neurodegenerative disorders are strongly associated with this kind of cellular damage.
Again, the mechanisms overlap.
The environments shaping our biology
If the body behaves like an ecosystem, then it is not surprising that the external environment also shapes our health.
Recent cardiovascular research increasingly recognises environmental stressors as significant contributors to disease risk.[4] These include air pollution, chronic noise exposure, extreme heat, chemical pollutants, and long-term psychological stress. Air pollution alone ranked fourth among global risk factors for mortality in the 2019 Global Burden of Disease analysis.[5]
All of these pressures influence the same biological pathways: inflammation, oxidative stress, and vascular damage.
Because the brain relies so heavily on the body’s vascular network, these environmental forces can also influence cognitive ageing.
The conditions we design into our cities, workplaces, and daily routines may be quietly shaping how well our brains age.
A design problem hiding in plain sight
Seen from this perspective, health is not just a medical issue. It is also a design challenge.
How we design our environments affects the biological systems we depend on.
Urban air quality affects vascular inflammation. Noise affects sleep. Green space affects stress and recovery.
These factors influence the infrastructure that supports cognition itself.
Biomimicry encourages designers to look at how nature creates resilient systems. One recurring strategy is the creation of conditions that allow healthy processes to emerge naturally.
Ecosystems do not micromanage individual organisms. Instead, they create environments where life can flourish.
The same principle may apply to human health.
Instead of focusing only on treating disease after it appears, we might also design environments that make healthy biological function more likely.
The everyday behaviours that support the system
Fortunately, the behaviours that support cardiovascular health also tend to support the brain.
Research repeatedly highlights a small set of habits that influence both systems.
Regular movement
Physical activity improves circulation, reduces inflammation, and increases blood flow to the brain. It also promotes neuroplasticity and hippocampal growth — the brain region most critical for memory and learning.[6]
Consistent sleep
During sleep, the brain clears metabolic waste and restores neural function. Research has shown that sleep is associated with a striking increase in the clearance of beta-amyloid, a protein implicated in Alzheimer’s disease.[7]
Whole-food dietary patterns
Diets rich in vegetables, whole grains, fish, nuts, and healthy fats support vascular health and reduce inflammatory stress.
Stress regulation
Practices that calm the nervous system — exercise, time in nature, reflection, or mindfulness — help prevent chronic activation of the stress response.
None of these interventions is dramatic. But over the years, small behaviours shape the conditions in which our biological systems operate.
Thinking like nature
One reason biomimicry is so powerful is that it changes how we frame problems.
Instead of asking how we fix a single issue, it asks: what conditions allow the whole system to work well?
Applied to health, this perspective shifts the focus from isolated symptoms to the environments and behaviours that support the body’s natural resilience.
The emerging science connecting heart health and brain health is a reminder that cognition itself depends on the health of these underlying systems.
Our bodies evolved to function within particular environmental conditions — movement, daylight, varied nutrition, and connection to the natural world.
When those conditions are present, many biological processes regulate themselves remarkably well.
When they are absent, problems begin to accumulate.
The bigger lesson
If there is one insight from living systems worth remembering, it is this: intelligence is supported by networks.
In the brain, those networks are neurones.
In the body, they are blood vessels and metabolic pathways.
In ecosystems, they are flows of energy and resources.
Damage the network, and the system struggles. Support the network, and complex behaviour becomes possible.
Protecting cardiovascular health, it turns out, may also be one of the most important ways to protect the brain.
And the environments we create around us — our cities, workplaces, and daily habits — play a larger role in that process than we often realise.
A new series: Lessons from the Connected Body
This article is the first in a series exploring how insights from biology can inform how we think about cognition, design, and human environments.
Future pieces will explore why walking often improves thinking, how sleep supports cognitive function, why time in nature affects attention and mood, what the microbiome might teach us about mental resilience, and how environmental design influences learning and creativity.
Biology is full of systems that have evolved to solve complex problems.
Looking closely at those systems may offer clues for designing healthier environments — and perhaps even more thoughtful technologies.
The treasure hunt continues.
References
[1]The Cerebral Circulation, Cipolla MJ. San Rafael (CA): Morgan & Claypool Life Sciences, 2009. Available at: https://www.ncbi.nlm.nih.gov/books/NBK53094/
[2]Ekblom-Bak E et al. ‘Cardiorespiratory fitness and inflammation in Swedish adults: a cross-sectional study’, Neurology, 2022. See also: Kivipelto M et al. ‘Midlife vascular risk factors and Alzheimer’s disease in later life’, BMJ, 2001.
[3]Ridker PM et al. ‘C-reactive protein, the metabolic syndrome, and risk of incident cardiovascular events’, Circulation, 2003. For the brain–inflammation link: Ageing Research Reviews, 2024 review on inflammation, oxidative stress and cognitive decline.
[4]ESC / ACC / AHA / WHF Joint Statement on Environmental Stressors and Cardiovascular Disease, Circulation, 2025. Available at: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.125.079034
[5]GBD 2019 Risk Factors Collaborators. ‘Global burden of 87 risk factors in 204 countries and territories, 1990–2019’, The Lancet, 2020; 396(10258): 1223–1249.
[6]Jimenez-Maldonado A et al. ‘Neuroprotective mechanisms of exercise: a review’, The Lancet, 2025. See also: Erickson KI et al. ‘Exercise training increases size of hippocampus and improves memory’, PNAS, 2011; 108(7): 3017–3022.
[7]Xie L et al. ‘Sleep Drives Metabolite Clearance from the Adult Brain’, Science, 2013; 342(6156): 373–377. Available at: https://www.science.org/doi/10.1126/science.1241224
AI was used as a Thinking Partner