Protecting Your Brain as You Age

TL;DR: Two people can carry similar changes in their brains and still think very differently at 80. Cognitive reserve research suggests decades of what they asked of their brains may explain part of the gap. Because memory begins with attention, where yours goes is worth noticing, though no one has shown that poor focus causes dementia. Nicole Hollar, pattern analyst and behavior change expert, sees this as a question of personal agency: some risk sits outside your control, and some of it belongs to the choices you repeat every day.

Forgetting why you walked into the kitchen can feel like a small preview of something bigger, especially when most of your day is spent with a phone in one hand and a dozen open tabs in your head. It is reasonable to wonder whether a distracted life is costing something you won't notice until later.

Research doesn’t seem to invoke panic or reassurance. University College London researchers followed 12,280 adults over 50 in the English Longitudinal Study of Ageing for 15 years. They combined education, occupation, and leisure activities into a measure of cognitive reserve, which is the brain's capacity to keep functioning when age or disease starts placing demands on it. People with high reserve had about a 35% lower risk of dementia than those with low reserve.

Yet, an analysis from the Rush Memory and Aging Project found that a similar association remained after accounting for the Alzheimer's and vascular pathology found in participants' brains at autopsy. Reserve did not appear to stop that pathology from forming. It appeared to change how well a person functioned alongside it, which may be why two people with similar changes can look so different.

This is why paying attention is so important. You can’t remember something you didn’t attempt to store. In classic experiments, people who divided their attention while learning new material remembered markedly less afterward, while dividing attention at retrieval costs far less. I wrote about what distraction costs at work in “Logged In, Checked Out.” This is the same habit with a longer time horizon. I am no medical researcher, however I do believe that the link from daily attention to lifelong reserve is a reasonable hypothesis, even if not a proven pathway.

The chicken-and-egg problem

A 2024 study in Age and Ageing pooled five cohorts from Finland and Sweden, 33,263 adults over 50, and found that people who stayed mentally, socially, and physically active had a lower risk of dementia within ten years of follow-up. Beyond ten years, that association faded toward nothing. The authors raised reverse causality as one explanation: an early dementia process may reduce a person's engagement years before diagnosis. Someone who quit the crossword may not have lost protection by quitting. Something may already have been changing.

So, I am not going to tell you a scattered mind gives you dementia. The evidence does not say that, and plenty of dementia has causes no amount of focus touches, genetics among them. The Lancet Commission's 2024 report identified 14 modifiable risk factors, from hearing loss to high blood pressure to social isolation, estimated to account for about 45% of dementia worldwide. That still leaves a great deal outside anyone's control, and it is a mistake to read every diagnosis as evidence that someone did something wrong.

Though my genes, my age, and much of my medical history are not mine to edit. What I attend to, what I learn, how I spend my hours, who I talk with, and whether I keep asking my brain to do something difficult are mine. None of it comes with a guarantee. I must believe, however, when we don’t ask our brain to develop goods habits including listening, focus, mind-quieting, even sustainable health habits, when things start to misfire why shouldn’t is release those elements first.

Questions for Reflection

1. When you start learning or hearing something important, where does your attention go in the first minute, and how often is part of you already somewhere else?
2. What is the most mentally demanding thing you did this week, and did you choose it or did it simply land on you?
3. Which things within your influence, such as hearing, blood pressure, movement, learning, or connection, have you been chalking up to "that's just aging"?

Frequently Asked Questions

What is cognitive reserve?

Cognitive reserve is the brain's capacity to keep working well despite age-related changes or disease. Researchers usually estimate it from education, occupation, and engaging leisure activity over a lifetime. It appears to influence how much impairment a person shows, and not whether changes in the brain occur.

Can you lower your risk of dementia as you get older?

Some risk can be influenced. The 2024 Lancet Commission estimated that about 45% of dementia could potentially be prevented if 14 modifiable factors, including hearing loss, high blood pressure, physical inactivity, and social isolation, were eliminated. That is an estimate about populations and not a guarantee for any one person.

Does constant distraction or multitasking cause memory loss?

Dividing attention while you are learning something reduces how well you remember it afterward, so a distracted day can produce ordinary forgetfulness. That is different from causing dementia, and no study has shown that it does. Memory changes that persist, worsen, or interfere with daily life deserve a conversation with a physician.