Life After Full-time Work Blog

Learn about preparing for life after full-time work through posts from Don's upcoming book.

# 101 Build Up A Brain Reserve (and a bonus)

How to help your brain power last longer


Before I get to this week’s post, here’s a bonus, related to the pandemic we’re fighting through.

It’s an article by Laurence B. Siegel

Larry (as I’ve known him for many years) is the best reviewer and interviewer I’ve ever come across (not to mention an inspiring author), and here he interviews Dr Drew Senyei to produce the most informative piece I’ve seen about the coronavirus. I didn’t realize, for example, that it’s an over-reaction by the immune system that creates potentially the most serious effects.


On a personal note, I’ve completed my 14 days of self-isolation. I find it interesting how my attitude changed, from initially considering myself imprisoned in a small space, to feeling, by the end, that I was protected in my fortress and being reluctant to go out again and be exposed to the danger.


You’ll remember that one of the topics I said I’m going to research is accumulating health. I’ve wondered if, in the same way that we can build up assets that we then draw upon for financial health later in life, we can do something similar with our physical and mental health. And one reader suggested that I shouldn’t wait until my research is complete, but instead should periodically post building blocks. Combine the two, and this blog post results.

This is about mental health, and about building up a personal brain reserve that gives us extended brain power later in life. (My thanks to Gordon for starting me off on this trail.)


We’re all different. Our bodies have essentially the same physical structure, but we’re not identical in the way we’re built. Using a computer analogy, we have different hardware, but we can still do the same sorts of things, though to different extents. Similarly our brains have different hardware, but we can still think in the same way. Our built-in brain software has common elements.

That’s how we start. Never mind the differences in size and capabilities between one person and another – that’s not my focus. What I’m looking at here is that each of us individually travels along our own life path with this common brain feature: that our brains decline in size as we age, and that the brain decline comes with a decline in cognitive capability. And so it would be interesting to find a way to slow down the decline, or even expand brain capacity. The financial analogue is to find a way to live happily on less money, so that our reserves last longer, or to even build an additional reserve.

In terms of our brain, the answer to those two desires seems to be: yes we can, and yes we can.


Here’s the normal way the brain changes over time.

We’re not born with full adult brain function. First as children, then as adolescents, our brains expand enormously. The number of neuronal connections (“synapses”) extends to almost one quadrillion. (OK, that’s 1,000 trillions, or a million billions. I have no concept of that number – it’s just ridiculously large.) And though by the age of six our brains are about 90% of full adult size, parts of it are still developing much later. The frontal lobes, responsible for what scientists call “executive functions” (planning, remembering, controlling ourselves), aren’t fully developed until around age 35.

It appears that brain shrinkage starts in our 30s or 40s: just as our bodies age physically, so too do our brains.

It’s not the neurons that vanish. Rather, they shrink, their dendrites (the branches that make connections) shrink and lose their spines, and then the synapses don’t connect as well as before. And typically this results both in brain shrinkage and in cognitive decline. In particular, it’s the memory that requires conscious retrieval that declines (whereas procedural memory, like riding a bike, doesn’t), along with shrinkage of those frontal lobes. It’s been observed that so-called “super-agers,” who have far better cognitive ability in old age than average, have also experienced the smallest brain shrinkage.

Possibly some of this shrinkage is a good thing, reflecting increased efficiency of the brain as we unconsciously get rid of connection that we don’t use all that much, and focus on aspects that are often noticeably better in middle age than they were before, like verbal ability, math, and spatial and abstract reasoning.

The areas that shrink fastest are actually the ones that matured latest, like the frontal lobes, the hippocampus (responsible for creating memories) and the cerebellum (responsible for motor functions) – more about them later. This is believed to be responsible for the “last in, first out” aspect of memory.


All of which suggests that, if we can find a way to slow down the decline, that would be very welcome.

Enter neuroplasticity, meaning that the brain is not so much a rigid structure as one that can be re-shaped. It turns out that the brain is able to reorganize itself and make new connections, as its environment changes. To some extent this slows down the decline. In addition, there are ways in which totally new connections are made, which in my retirement finance analogy is equivalent to creating new savings.

And so we need to change, or add to, the brain’s normal environment. How?

Here are some of the ways:

  • Get enough sleep. We go through many cycles of sleep each night, the final stage of each cycle being “slow-wave deep sleep,” when the brain slows down and our glial cells release cerebral spinal fluid that essentially clears away the metabolic waste that accumulated while we were awake. So while we sleep, the brain constantly repairs itself, and organizes memory (in addition to other benefits in our body). Without enough of this we feel sluggish and, even if we’re not aware of it, over time our brain function can decline. I don’t know if there’s a definitive answer, as people need different amounts of sleep, but I gather that five 90-minute sleep cycles are healthy, perhaps four in our 70s.
  • Exercise. This generates new synapses, in addition to positive effects on our body.
  • Encounter new experiences. This creates those environmental changes that I mentioned. While I use a single heading here, in fact there are so many ways to achieve this. For example: travel; learn a new language; learn a new musical instrument; create art; read fiction, to generate a new mindset, even if temporarily; learn new moves, like dancing or exercising your non-dominant hand; try unusual ways to remember things, like a list that you classify by a succession of images or by an acronym. You get the idea: it’s novelty that requires the brain to create new pathways. Constantly doing crosswords and sudokus doesn’t achieve this, no matter how difficult they may be.
  • Reduce stress. Stress reduces neuroplasticity. Sometimes you can help reduce stress by meditation, gardening, walking, or surrounding yourself with nature.
  • Here’s a strange one: put as much of your life as possible on autopilot. In other words, make it repetitive, and not requiring active thought. Why? Because this frees up both time and your mind for all those new experiences.

All of these are ways to reduce the rate of decline.


Neuroplasticity shows itself in other circumstances too. I found it particularly interesting to read about it in connection with strokes and Alzheimer’s, because that’s when totally new pathways are created.

We know about heart attacks. A stroke is a brain attack. Areas of the brain are destroyed, and whatever functions rely on pathways through those areas are also destroyed.

With Alzheimer’s, it is believed that amyloid beta deposited daily in the brain’s synapses isn’t fully washed away during sleep, and gradually neural connections fill up with amyloid plaques, becoming tangles and then inflamed, and of course the cells involved eventually cease to operate.

Yet studies have shown that people who have had strokes, and people whose brains are filled with plaque, can operate quite normally. Clearly there are totally new pathways that have been formed. This is called creating a “brain reserve.” And the resulting avoidance of cognitive symptoms is called a “cognitive reserve.” Again, the computer analogy works here: the brain reserve is like hardware, and the cognitive reserve like software.

It’s the cerebellum and the hippocampus that are at work, here. The cerebellum is the area of the brain at the base of our skull, and you’ll remember that it’s largely responsible for movement control, though it also has many other functions. The hippocampus is the area responsible for initiating memory formation. Together they contain more neurons than any other part of the brain, and so they are the creative points for brain plasticity.

Quite simply, they generate new neurons that form new connections with old neurons elsewhere in the brain, and in so doing they create new pathways. It is thought that there’s a Darwinian effect in action, and the new neurons tend to win the battle for survival and help to restore some of the functions of the old pathways.

Sorry to keep pushing the investment analogy, but I think of this as the neural equivalent of restoring reserves after a market collapse.


Not surprisingly, this is a field being explored, rather than one that is well established. For what it’s worth, while there are many pieces I looked at, the ones that got me started are and Also check out the short but outstanding TED talk


I showed this draft blog post to a friend. He generously acknowledged that the facts I laid out are accurate, but added that it’s a bit too technical/medical for many readers. His own take on it is so beautifully and simply expressed that with his permission I’m using it as the takeaway, below.



The brain is like a muscle. Exercise it in a variety of ways to build resiliency.


I have written about retirement planning before and some of that material also relates to topics or issues that are being discussed here. Where relevant I draw on material from three sources: The Retirement Plan Solution (co-authored with Bob Collie and Matt Smith, published by John Wiley & Sons, Inc., 2009), my foreword to Someday Rich (by Timothy Noonan and Matt Smith, also published by Wiley, 2012), and my occasional column The Art of Investment in the FT Money supplement of The Financial Times, published in the UK. I am grateful to the other authors and to The Financial Times for permission to use the material here.

6 Responses to “# 101 Build Up A Brain Reserve (and a bonus)”

  1. Peter Casquinha (CPBI) says:

    Hi Don,
    This is excellent. Thank you for sharing this. Enjoyed following your blog on the various aspects of post retirement. Started mine on Jan 1st 2020 and just back from my first “snowbird” winter in the south. Unfortunately cut short due to COVID19. Like you I am finished my two week quarantine but this doesn’t change anything in our behaviour with our world at a standstill and most in self-isolation. Over the last few years I have been interested in brain plasticity and particularly, due to my mother’s condition, the research on Alzheimers. Look forward to more info that you manage to come across.
    Warm regards and to you and your family, STAY HEALTHY…

    • Don Ezra says:

      Thanks very much, Peter. All the best in your own Life Two! What a different and difficult world we’re in, right now.

  2. Ted Harris says:

    Eat well, sleep well and exercise your brain as well as your body.

    Two remarkable books that are very well written and cover the latest in neuroplasticity are “The Brain That Changes Itself” and “The Brain’s Way of Healing”. Both are by Dr. Norman Doidge and are packed with real life examples of many types. For instance, a chapter in the second book deals with how a doctor and his patient use neuroplasticity to tackle Parkinson’s.

    The Covid interview is a good read.

    By the way, this virus has got to get under control – because we’re overdue for lunch!

    • Don Ezra says:

      Thanks very much, Ted. I’ll follow up on the Doidge references — another friend just emailed me about him too. Won’t it be nice when we can return to normal interaction — looking forward to it!

  3. Cindy Deere says:

    Hi Don, I love this! What a nice complement to the financial topics that you’ve already covered so well! Can’t wait to read more! You’ve now challenged me to do more than crosswords and sudoku, and I’m very pleased to know that reading novels is a good thing! Take care and write more!

    • Don Ezra says:

      Thanks, Cindy, I’m so glad to hear that! Yes, re crosswords and sudoku, I took that thought as a comment to myself, since I spend a lot of time doing them. I need to branch out into unfamiliar territory. The world of music beckons, because I’ve never played an instrument in my life and I’m so totally linear — trying to engage several fingers and both hands at the same time on a piano is a daunting challenge, as it’s so unlike me.

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