Brain Health at Every Age

Forties: the decade nobody treats as relevant

Processing speed has already begun to slow, and almost nobody notices, because the change is small and compensation is easy when the rest of the machinery is intact. This is also the decade in which the measurements that predict later cognition are taken — and mostly are not.

One item dominates this decade: blood pressure. Midlife hypertension's link to later cognitive outcomes is one of the sturdier findings available, and the inconvenient part concerns which readings carry weight. Not the ones recorded at seventy-five, by which point the question has answered itself, but the ones nobody thinks to take at forty-six.

Fifties: the habits set here are the ones you keep

Two things happen in this decade. Sleep quality tends to deteriorate, often without being recognised as a problem rather than an inevitability. And a working life at its busiest makes it easy to drop the exercise habit that is doing more for your cognition than anything else available.

If snoring has been mentioned, or anybody has described pauses in your breathing at night, that is worth investigating properly rather than joking about. Sleep apnoea is common, under-diagnosed, and presses on exactly the systems this page is about.

Sixties: hearing, and the thing nobody does about it

Hearing moves to the top of the list here, and gets ignored more thoroughly than anything else on it. Among modifiable factors, leaving hearing loss untreated sits at the heavy end of the published associations with later decline — and the typical delay between a person noticing the problem and acting on it is measured in years rather than months.

There is a second, more immediate reason it matters. Working hard to hear in a noisy room consumes exactly the attention that storing a new name requires. Somebody who cannot quite follow a conversation at a family table is not failing to remember it. They are failing to receive it.

Seventies and beyond: company, and not stopping

What threatens this decade is retreat: out of conversation, out of movement, out of the mildly effortful business of other people's company. Talking to somebody makes demands a puzzle book never will, for the simple reason that a person cannot be anticipated and a grid of clues can.

It is also the decade in which people most often assume the useful window has closed. It has not. Hearing treated at seventy-four still carries benefit. Somebody who starts walking at seventy-one is not too late to the intervention with the best evidence base in the field.

The part that stays constant

Beneath the decade-by-decade shuffling, the same half-dozen items hold their places throughout: what you can hear, what your blood pressure reads, how much you move, how you sleep, who you see, and what you eat. Only the question of which one is currently being let slide actually changes.