16th Feb 2026

Newsletter Monday

Hello Reader,

​I read a really interesting article in New Scientist yesterday about a dementia study.

Most of these stories blur into one another, but this one stood out immediately because it followed people for 20 years.

That’s rare.

As usual, I read it with one question in mind: what can we reasonably learn from this that might change how we live?

One of the frustrations with dementia research is time.

Alzheimer’s disease (just one subtype of dementia) is thought to begin 15–20 years before symptoms become obvious.

The pathology is present long before memory problems appear. That makes short-term studies inherently limited. They simply don’t run long enough to capture meaningful outcomes.

This one did, I mean 20 years is a long study.

Retirement

It also made me think about retirement. Not mine, I can’t even finalise the summer holiday, but retirement as a concept.

In The Psychology of Money, Morgan Housel points out that retirement, as we know it - decades of post-work life - is historically new.

For most of human history, people didn’t stop contributing at a fixed age and then enter prolonged leisure. The structure of modern retirement is unusual in society, I'd never thought of it that way before.

In clinic, I hear patients talk constantly about wanting to retire.

I also hear a lot of NHS staff talk about it too.

But what they're usually yearning for is freedom, not idleness.

The freedom to choose how they spend their time.

And yet it’s striking how often I hear, “I retired and then my body started to go wrong.”

Sometimes that’s simply the first opportunity they’ve had to notice symptoms. Sometimes it’s the sudden loss of structure, challenge, and purpose.

So how does this link to the ACTIVE study?

The trial followed around 2,000 older adults who were randomised to different types of cognitive training or to a control group.

The intervention that appeared to make a difference was called “speed of processing” training - and it wasn’t gentle.

Participants had to rapidly identify and locate visual targets under increasing time pressure. The task adapted to their performance, meaning it became harder as they improved.

It required sustained attention, rapid decision-making, divided attention, and visual discrimination - all under speed constraints.

• It was effortful.
• It was uncomfortable.
• It demanded improvement.

This wasn’t passive stimulation.

It wasn’t chatting.

It wasn’t a crossword once a week

Twenty years later, roughly 49% of people in the control group had a dementia diagnosis compared with around 40% in the group that completed this structured training with boosters. That is an absolute difference of about nine percentage points over two decades.

That is significant.

What does it tell us in the real world?

But that the brain, like muscle and bone, appears to respond to load - especially adaptive, challenging load.

If you want real-world equivalents, think along these lines:

• Learning a new language to conversational fluency
• Learning a musical instrument beyond the basics
• Complex strategy games played competitively
• Structured dance choreography
• Martial arts
• Strength training with progressive programming (motor learning counts)
• Teaching or mentoring in a way that forces you to stay sharp

The common thread is sustained, effortful, progressive challenge.

This aligns very closely with what Sir Muir Gray has argued for years in books like Sod 70!.

Healthy ageing is active.

Muscle needs load.

Bone needs load.

And increasingly, the evidence shows the brain does too.

If Alzheimer’s pathology begins decades before diagnosis, then what you do in your 50s and 60s - perhaps just as you enter retirement - may influence how much cognitive reserve you build before symptoms ever appear.

This is hopeful, not because it promises immunity.

It doesn’t.

Even in the training group, 4 in 10 people developed dementia over 20 years.

But that difference - about nine fewer people per hundred over two decades - is not trivial.

Retirement does not have to mean withdrawal from challenge.

It can mean redesigning the kind of challenge you choose.
And that is a far more interesting version of freedom.