Issue #483: How You Impact the 5 Lives of Your Brain
Good morning. It’s Tuesday, December 9th, 2025.
In today’s email:
Learn: Your Brain Has 5 Lives
Try: Walk…Every Day
Read: Find a Good Book
In the News: Wellness to Top $10T
Stat of the Day
The percentage of dementia cases that can be prevented through lifestyle. (Lancet Commission on Dementia Prevention, Intervention, and Care - 2020)
Learn
Your Brain Has 5 Lives
A new study of nearly 4,000 brain scans - from newborns to 90-year-olds - shows us exactly how our brain develops over the course of our life.
Our brain doesn’t follow a straight line. It shifts how it works, how it organizes. And the biggest changes happen at ages we don’t usually think about: 9, 32, 66, and 83.
These findings are just the beginning to help us understand how we learn, why we start to forget, and what we can do to maintain our cognitive health for our entire life.
0 - 9: The Builder Years
The first decade is a construction zone. We typically think about our kids constantly learning. At this point our brain is creating new synapses (neuron connections) nonstop. But what we didn’t realize as much is that the brain is deleting almost just as many synapses too. Anything not being used is eliminated.
That’s why it’s so important for kids to experiment - they need to try stuff, build, test, repeat.
What survives this phase becomes the default wiring of the adult brain.
For all the parents out there - here’s what our kids need most:
Sleep: Kids need more than we think - it’s how the brain consolidates learning and chooses which connections to keep and which to delete. An early bedtime is essential for long-term cognitive health.
Movement: Not just sports. Climbing, jumping, biking, chasing - all of it strengthens motor and cognitive networks. Get ‘em off the couch and keep them moving!
Language + Curiosity: Ask your kids questions - make them think. The more they’re exposed to things they don’t know, the more experimentation and the more the tracks are laid for a strong network of neural connections that will last for decades.
If you’re parenting a young child, think less about “performance” and more about “experimentation.” The brain is soaking up signals about what matters.
9 - 32: The Long Adolescence (Yes, It Really Lasts This Long)
We think of adolescence ending around 18 (or maybe like car rental companies at 25). But this study shows that our brain is still refining long-range wiring and “adult mode” decision-making well into our early 30s.
During this window, the brain gets better at having different regions communicate with each other. This is when we can “connect the dots” and build insights from the inputs we take in from the world.
Why this is so important:
We aren’t done growing in our 20s - these are still the years priming our brain to set the foundation for the rest of our lives.
Good habits - consistent exercise, constant learning, and figuring out how to regulate our emotions in our 20s - matter a lot as we continue to tune our circuits.
32 - 66: The Strength Phase
Around 32, the brain shifts direction again. Instead of building more connections across different regions of the brain, it focuses more on “local specialization.”
This is when we start to be able to better recognize patterns and when we can interpret the world around us. We start to develop judgment, not just basic memory.
This is when we’re at our cognitive peak - but that doesn’t mean we’re done learning. We might not be adding as many new neural connections, but we better strengthen, refine, and reinforce what we’ve got.
This doesn’t just happen - to maintain our cognitive health into our mid-60s and beyond, we need to feed our brain the right fuel, and keep out the unnecessary junk.
What keeps your brain strong through this long phase:
Consistent movement: Supports strong blood flow to your brain - the foundation of cognition.
Stable sleep + stress patterns: Protect white matter and prevent wear-and-tear by getting enough sleep and managing stress so you don’t stay in constant fight-or-flight mode.
Challenging work and learning: Keeps networks flexible instead of rigid.
Think of this stage like strength training for your brain. You may not be building new muscle, but you’re keeping what you have powerful and resilient.
66 - 83: The Wisdom Years
By this point, our brain is laser-focused on connections within specific regions. That means we might forget names or specific details might slip our mind. We feel those “aging” moments when we wonder why our memory isn’t what it used to be.
But there’s a positive trade-off - this shift makes it easier to lean on experience and judgment. There’s a reason so many cultures talk of elders having more wisdom. That’s what our brains are built for at this stage.
Less trivia, more truth.
But you’ve got to continue to protect your brain to keep it high-functioning:
Real Nutrition: Feed it fuel, not poison.
Move, Move (and Move Some More): Strength, balance, and cardio all matter.
Stay mentally and socially engaged. Your brain needs other people as much as it needs oxygen.
This isn’t decline. It’s a different way of solving problems - one that relies on depth, not speed.
83+: The Essentials
After this point, the brain shows fewer dramatic structural shifts and goes into more of a survival mode.
It’s all about keeping the fundamentals strong: hearing, vision, movement, nutrition, and connection. Small lapses in any of these ripple quickly into cognitive function.
So Why Does the Brain Change Like This?
We’re still figuring that out. But it seems like the brain is constantly optimizing based on energy and efficiency.
Early life is about building as much capacity as possible.
Young adulthood is about connecting it.
Midlife is about stabilizing it.
Later life is about conserving it.
We can affect when and how this happens. These phases aren’t certain - we can influence how our brain changes and the level of functioning at each stage.
Just remember - your brain responds to what you do. Not what you intend to do. Not what you used to do. What you do now.
So how are you supporting your brain?
Try
Walk - Every Day (for at least 30 min)
One of the best ways to protect your brain - lower your blood pressure.
High blood pressure reduces oxygen and nutrient flow to the brain. People with hypertension (systolic blood pressure - the “first number” - over 130 mmHg) is associated with 30-60% higher risk of dementia.
Walking can lower systolic blood pressure by 5-8 mmHg - as effective as most medications.
Make it a goal to get out there every day - even if it’s more of a “hike” than walk like it is for Max in Chicago this time of year.
Chicago - Dec 2025
Thrive25 Partner Spotlight
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If you know golf, you know the ball matters.
TP5 and TP5x are the balls top players switch to when they want tour-level speed, control, and feel. And this holiday season, TaylorMade has dropped the price to just $44.99.
It’s the perfect gift for the golfer who’s always chasing more consistency or the friend who keeps “borrowing” your balls on the course. Stock up now, for less, and make every round feel a lot more dialed in
Not good when you consider that 40% of adults report not reading books at all - and that’s probably an underestimate as more people will respond to surveys that they do read books, but in reality it’s just sitting on their nightstand.
H&L in the News
Clean Blood: Therapeutic plasma exchange (TPE) involves drawing your blood, separating the plasma (liquid part of blood) and returning blood cells without the micro-plastics and toxins. The company Circulate Health just raised another round of funding - but it still costs a consumer $10K. (Longevity.Technology)
A $10T Market: Global wellness is expected to double between 2019 and 2029 - when it will hit 14-digits. There’s no slowing down in this market. (Fitt Insider)
Lower Salt, Don't Sacrifice Taste: Most Americans over-salt daily. These expert-backed strategies - like potassium salt swaps, umami boosts, and smart label reading - help cut sodium without sacrificing flavor or your health. (NYTimes)
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We’re 40-something dads that felt our bodies and minds start to slow down and we’re not ready for that. We found too much information on every subject. So we started Thrive25 to transform what we’ve learned into something useful for the rest of us to spend just 3-5 min a day to optimize our health & longevity.
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The information in this newsletter is for informational purposes only and may not be appropriate or applicable based on your individual circumstances. Thrive25, Inc. does not provide medical, professional, or licensed advice. Please connect with your healthcare professional for medical advice specific to your health needs.