"Is it too late to start?" is one of the most common — and most understandable — questions about staying mentally active. A 2026 study from Rush University offers a genuinely reassuring, evidence-based answer, built from one of the more thorough long-term studies on the subject to date.

What researchers did

Researchers followed 1,939 participants (average age about 80 at the start) for an average of 7.6 years, tracking detailed histories of mentally engaging activity across each person's entire life — reading, learning new skills, visiting museums, and similar activities — not just what people were doing at the time of the study.

What they found

People in the top 10% for lifetime mental engagement developed noticeable Alzheimer's symptoms an average of five years later than people in the bottom 10%, and reached earlier stages of measurable cognitive difficulty about seven years later. Strikingly, this held even among participants whose brain scans, examined after death, showed similar physical changes associated with Alzheimer's disease — suggesting a genuinely protective effect on how the brain functions, independent of the physical changes themselves.

Why "lifetime," not "starting today," is the finding

This study's real contribution is the word "lifetime" — it is not simply "people who currently do puzzles score better," it is a multi-decade pattern. That is a meaningfully different, and stronger, kind of finding than a short study can offer.

What this means if you're starting later

The honest reading is not "it's too late unless you started decades ago" — the study measured a real correlation across whole lives, not a hard cutoff, and starting now is still starting something that did not exist before. The Habit of Learning Something New and Picking Up a Skill You Let Go are both about exactly that: today is the earliest day left to add to your own total.

What we won't claim

This is one large observational study, and it cannot promise any individual person a specific outcome or number of years — brains and lives vary too much for that. What it does offer is some of the most direct evidence available that mental engagement, sustained over years rather than days, is linked to a real, measurable difference.