The Best Time to Prevent Cognitive Decline Is Before It Starts

One of the hardest things about dementia is that it doesn’t just happen to one person. It happens to a family.

I saw that up close when helping my Mom care for a parent with dementia. The disease slowly takes things that feel almost sacred: memory, independence, personality, rhythm, confidence and connection. And for the people who love that person, it creates a kind of grief that starts long before goodbye.

That experience changed how I think about longevity. Living longer only matters if we’re also preserving the parts of ourselves that make life feel like life.

That’s why cognitive health can’t be something we start caring about once we forget names, lose our train of thought or feel like our brain is slipping. By the time symptoms show up, many of the underlying biological changes may have been building for years.

So the question is simple: What are we doing now to protect the brain we want later?

Dementia isn’t completely preventable. Genetics matter. Age matters. Luck matters.

But lifestyle and medical risk factors matter too.

The 2024 Lancet Commission on dementia prevention estimated that addressing 14 modifiable risk factors across life could prevent or delay about 45% of dementia cases. Those factors include hearing loss, high blood pressure, physical inactivity, diabetes, smoking, obesity, depression, excessive alcohol, traumatic brain injury, social isolation, air pollution, lower education, high LDL cholesterol and untreated vision loss.

That number should stop us in our tracks. Not because it means dementia is anyone’s fault. It isn’t. But because it means prevention isn’t some vague wellness concept. It’s a practical, measurable set of actions we can begin earlier than most people think.

One of the most hopeful ideas in brain health is neuroplasticity: the brain’s ability to adapt, remodel and strengthen over time.

A big part of that story involves BDNF, or brain-derived neurotrophic factor. Think of BDNF as one of the brain’s growth and maintenance signals. It supports neurons, helps with learning and memory and is one reason exercise appears to be so powerful for cognitive health.

Dr. Rhonda Patrick has done a great job popularizing this concept through her work at FoundMyFitness, especially around the role of vigorous exercise, lactate and BDNF. One of the key ideas she’s highlighted is that lactate isn’t just a waste product from hard exercise. It may also act as a signaling molecule that helps connect intense physical effort to brain adaptation.

Dr. Patrick has illuminated how higher lactate after vigorous exercise is linked to improved executive function and that high-intensity interval training may produce larger BDNF responses than moderate continuous exercise.

This doesn’t mean you need to destroy yourself in every workout. It means intensity has a role. Zone 2 builds the base, strength training protects the system and small doses of vigorous effort may provide a unique brain-health signal.

Curious about BDNF? I wrote a deeper dive on why everyone is talking about it, what it does and how to think about it practically here: Why Everyone Is Talking About BDNF⁠.

This post is sponsored by Cenegenics, a leader in personalized longevity medicine.

What I appreciate about the personalized medicine model is that it starts with a simple idea: don’t wait for decline to become obvious before paying attention.

Cognitive health is deeply connected to vascular health, metabolic health, hormone health, inflammation, sleep, fitness, nutrition and stress. A more proactive model of care looks at the whole system earlier, when there’s still time to make meaningful changes.

And that’s the broader message of this post: whether it’s through your physician, your own tracking, better habits or a more comprehensive longevity approach, the goal is to take action before symptoms force action.

Visit Cenegenics.com to learn more and for a deeper dive, check out my review of Cenegenics: Why More People Are Turning to Physician-Led Longevity Programs.

Here’s where I’d start.

Exercise may be the closest thing we have to a brain-health keystone habit.

The practical target isn’t complicated: aim for 150+ minutes per week of zone 2-style cardio, like brisk walking, cycling, swimming, hiking or anything that gets your heart rate up while still allowing conversation.

Layer in 2–3 days per week of strength training. Muscle is metabolic armor. Better metabolic health means better vascular health. Better vascular health means better brain health.

Then add a few short bursts of higher intensity when appropriate. That could mean hill sprints, intervals or faster efforts on a bike, rower or treadmill. The goal isn’t to suffer. The goal is to remind the brain and body that they still need to adapt.

Sleep is when the brain consolidates memories, regulates emotion and clears waste products. Poor sleep isn’t just an annoyance. It’s a cognitive risk signal.

The basics still matter: keep a consistent sleep and wake time, get morning light, limit alcohol near bedtime and treat snoring, gasping or suspected sleep apnea seriously.

Also, stop pretending 5.5 hours is “fine” because you can still function. There’s a difference between surviving the day and protecting your brain for the next 30 years.

We tend to think of blood pressure as a heart issue. It’s also a brain issue.

In the SPRINT MIND randomized clinical trial, intensive systolic blood pressure treatment significantly reduced the risk of mild cognitive impairment compared with standard treatment, though the reduction in probable dementia didn’t reach statistical significance in the primary analysis.

That nuance matters. This isn’t a license to chase lower numbers blindly. Blood pressure targets should be individualized with a clinician.

But it is a reminder that the small vessels feeding the brain matter. Decades of elevated pressure can damage the very infrastructure your cognition depends on.

Know your numbers. Track them. Act early.

This one surprises people.

Hearing loss is one of the most important modifiable dementia risk factors, in part because it may increase cognitive load, reduce social engagement and make the brain work harder just to interpret the world.

Even beyond dementia risk, treating hearing loss helps people stay connected. And connection is brain health.

If you’re asking people to repeat themselves, avoiding noisy restaurants or pretending you heard something when you didn’t, don’t tough it out. Get tested.

Loneliness isn’t just a feeling. It’s a risk factor.

This is one of the reasons dementia can be so cruel. The disease disconnects people from the world, but disconnection itself may also increase risk.

So the prescription here is both simple and hard: schedule recurring time with friends, join groups where people expect you to show up, call family, walk with someone, volunteer and say yes more often than feels convenient.

A sharper brain later may depend, in part, on deeper relationships now.

The brain is an energy-hungry organ. It depends on blood flow, insulin sensitivity, oxygen, nutrients and healthy vessels.

So the boring stuff isn’t boring. It’s foundational.

Manage LDL cholesterol. Address insulin resistance. Don’t smoke. Limit alcohol. Protect your head. Treat depression. Correct vision loss. Eat mostly whole foods. Move after meals.

These don’t sound like “brain hacks,” but they’re exactly the kinds of levers that show up again and again in dementia prevention research.

The unsexy truth is that the brain often reflects the health of the system it lives in.

The point is direction.

You don’t need to become a monk, wear 12 devices or optimize every minute of your life. But you do need to stop thinking of cognitive decline as something that only belongs to “old age.”

The prevention window opens much earlier.

It opens in your 30s when you decide whether exercise is optional. It opens in your 40s when blood pressure, LDL and sleep debt start compounding. It opens in your 50s when hearing, social connection and metabolic health become impossible to ignore.

And it stays open later than we think, because the brain remains responsive to better inputs.

For me, this is personal. Watching dementia up close made one thing very clear: protecting cognitive health isn’t just about protecting memory.

It’s about protecting dignity. It’s about protecting family. It’s about giving the people we love more years with the version of us they recognize.

So start before symptoms.

That’s the window.

Yours in Health,

Ryan Frankel