Neuroscientist Warns: These Daily Habits Are Raising Your Dementia Risk
How we use our brains is the primary determinant of how they will function. Up to 45% of dementias may be preventable through lifestyle choices. The key is the 3S Model: Stimulus (challenging your brain through deep learning and social interaction), Supply (cardiovascular health, metabolic health, a
2h 14mKey Takeaway
How we use our brains is the primary determinant of how they will function. Up to 45% of dementias may be preventable through lifestyle choices. The key is the 3S Model: Stimulus (challenging your brain through deep learning and social interaction), Supply (cardiovascular health, metabolic health, and essential nutrients), and Support (quality sleep, stress management, avoiding toxins). Start with one change—like improving sleep or learning a new skill—and the entire network shifts in your favor.
Episode Overview
Dr. Tommy Wood, a UK-trained physician specializing in brain health, explains that up to 45% of dementias are potentially preventable through modifiable lifestyle factors. He introduces the 3S Model (Stimulus, Supply, Support) as a framework for maintaining cognitive function across the lifespan. The episode covers how cardiovascular health, metabolic health, cognitive stimulation, social interaction, nutrition, and sleep all interact to determine brain function. Wood challenges the outdated belief that cognitive decline is inevitable, presenting evidence that the adult brain remains plastic and capable of adaptation well into later life.
Key Insights
Dementia is largely preventable through lifestyle choices
The Lancet Commission on Dementia Prevention estimates that 45% of dementias are potentially preventable by addressing modifiable risk factors. These include cardiovascular health markers (high blood pressure, diabetes), lifestyle factors (smoking, alcohol, air pollution), sensory input (hearing and vision loss), cognitive stimulation (education, complex work), and head trauma. Some experts believe the preventable proportion could be even higher than 45%.
The 3S Model: Stimulus, Supply, and Support
Brain health operates like physical fitness: Stimulus (how you use your brain through learning, skill development, and social interaction) is the primary driver. Supply (cardiovascular health, metabolic health, nutrients, energy) enables the brain to respond to stimulation. Support (sleep, hormones, stress management, avoiding toxins) allows adaptation and growth. These three elements interact synergistically—improving one area naturally improves others.
Cognitive decline after retirement accelerates due to loss of stimulation
Research shows cognitive function often declines more rapidly after retirement, not because of aging itself, but because people lose the complex cognitive stimulation and social interaction they received from work. The brain adapts to how it's used—when we stop challenging it with deep learning, skill development, and meaningful social engagement, function deteriorates. Maintaining these stimuli is critical in later life.
Multitasking and constant distraction are reshaping our brains negatively
People who frequently multitask across multiple media (Instagram + Netflix + Zoom) actually get better at multitasking but become more distractible overall. Their brains adapt by reducing their ability to filter out peripheral information, impairing deep focused work. The human brain cannot truly multitask—it can only rapidly switch attention, and this constant switching prevents the deep engagement necessary for cognitive growth and long-term brain health.
AI can be a cognitive orthotic or prosthetic—choose wisely
AI tools can enhance cognitive function (orthotic) or replace it (prosthetic). Studies show students who write essays themselves first, then use AI to refine and improve their work, perform best. This requires doing the cognitive heavy lifting yourself, then using AI to expand capabilities. If we use AI to offload thinking entirely, we lose those cognitive functions—just as unused muscles atrophy.
The adult brain remains plastic—you can still learn and adapt
Contrary to outdated beliefs, randomized controlled trials show people in their 60s, 70s, and 80s demonstrate structural brain changes and improved cognitive function when learning languages, music, or new motor skills. Learning may take slightly longer than in youth, not because the brain can't change, but because it's already optimized for your current environment. True focused engagement drives neuroplastic change at any age.
Cardiovascular health is foundational to brain health
Improving cardiovascular disease treatment has reduced age-specific dementia incidence over the past decades. Blood pressure, blood sugar regulation, HDL cholesterol, and triglycerides are all significant predictors of dementia risk. Both vascular dementia (10-20% of cases) and Alzheimer's disease (60-80% of cases) have vascular components. Good metabolic health ensures adequate blood flow and energy supply to activated brain regions.
Notable Quotes
"How we use our brains is the primary determinant of how they will function."
"If some proportion of dementias are preventable, then we must be able to change the trajectory of cognitive function and cognitive decline."
"We're chronically overstimulated while being under stimulated at the same time. We're constantly bombarded with multitasking and multimedia and social media and these things that don't truly drive improvements in brain function and feeling overwhelmed because of it whilst not being able to attend to the real focused deep learning and skill development which is what really drives brain function."
"The best way to minimize your risk of dementia is not sit at home by yourself jugging supplements. It's going to be much more about [engagement with life]."
"More than 50% of people maintained cognitive function from their 50s into their 60s, 70s and 80s. Nowadays we call people who do that super agers right because we think it's so unusual but actually we knew even back then that the majority of people sort of 50 60% maintained cognitive function into those later decades."
Action Items
-
1
Engage in deep, focused learning or skill development
Challenge your brain with complex tasks that require sustained attention: learn a musical instrument, study a new language, develop complex motor skills, or pursue education. Avoid superficial multitasking and instead dedicate focused blocks of time to skill acquisition. This provides the primary stimulus for cognitive adaptation and maintenance.
-
2
Prioritize cardiovascular and metabolic health
Monitor and manage blood pressure, blood sugar, HDL cholesterol, and triglycerides—all significant predictors of dementia risk. Regular exercise improves cardiovascular health and produces brain-derived neurotrophic factor (BDNF). Treat metabolic dysfunction early, as it impairs the brain's blood flow response and energy supply when you engage in cognitive tasks.
-
3
Protect and optimize sleep quality
Sleep is when synapses generated during learning are cemented and refined. It's the critical recovery period for cognitive adaptation—just as muscles grow during rest, the brain consolidates new skills and connections during sleep. Treat sleep as non-negotiable support for brain health.
-
4
Use technology as a cognitive orthotic, not a prosthetic
Do the cognitive work yourself first, then use AI or other tools to refine and expand your thinking. Write your own essays, solve problems independently, synthesize information manually—then use technology to critique, improve, or broaden your work. Avoid offloading thinking entirely, which causes cognitive atrophy.