A three-year study tracking adults aged 19 to 94 has found that the brain can continue improving well into old age, challenging one of medicine’s most persistent assumptions.

For decades, it was widely accepted that cognitive decline was an inevitable part of ageing. A new study published in Scientific Reports suggests that this assumption may need to be reconsidered.

Researchers at the Centre for Brain Health at the University of Texas at Dallas tracked 3,966 adults aged between 19 and 94 over three years. They found that brain health—measured across thinking ability, emotional stability, and social connectedness—continued to improve throughout the study period, including among participants in their eighties and nineties.

The study, titled “Measuring and Increasing the Brain Health Span across Adulthood: A Public Health Imperative,” was published in Scientific Reports, a Nature journal. It analysed data from the Brain Health Project, an online initiative launched by the centre in 2020.

Participants used an online platform offering brief training sessions, some lasting as little as five minutes. Their progress was tracked using the Brain Health Index, which measures three dimensions: Connectedness, which assesses a person’s sense of social and purposeful engagement; Clarity, which evaluates thinking and reasoning ability; and Emotional Balance, which measures mental well-being.

The index was assessed every six months, giving researchers seven data points over the three-year period. The gains were substantial. By the final assessment, participants showed an overall improvement that researchers described as reflecting a very large effect size. Every six-month interval produced statistically significant growth.

The study’s abstract noted that the results “demonstrate sustained improvements in overall BHI and component factors, independent of baseline scores.”

Who benefited and how much

One of the more striking findings concerned participants who scored lowest at the start. Those in the bottom quarter showed the steepest improvement over time. The study also found that participants who began with higher scores continued to make comparable gains. Nobody stopped improving simply because they were already doing well.

The gains were consistent regardless of age, gender, or education level. A 70-year-old and a 30-year-old saw broadly similar benefits. The study noted that this “reinforces the idea that adults can optimize their brain health at any age and supports the recommendation to begin proactive brain health practices early in adulthood and continue throughout the adult lifespan.”

Researchers also measured how actively participants used the platform’s tools, which included cognitive training modules, daily habit tracking, virtual coaching, and educational resources. Participants were divided into low-, modest-, and high-utilisation groups.

The difference between the groups was clear. High engagement produced the greatest gains, while low engagement produced the least. Participants who began with low engagement but increased their use during the second six months showed stronger improvements by the one-year mark. Those who remained low utilizers “had no change on their brain health indices through one year.”

The pattern did not vary by age or gender. A more engaged older woman and a more engaged younger man were equally likely to improve. The study noted that “higher utilization entailed consistent engagement with the online tools, assessments, coaching sessions, strategy-based micro-learnings, and habit-tracking, and was associated with greater gains in brain health over the 3-year follow-up period.”

The researchers argued that improvement was driven not simply by repeated exposure to training content, but by the development of self-agency—the belief that people can actively shape their own brain health. The study stated that the “most plausible explanations concern the possibility that learning strategies to control one’s brain function and brain health make participants feel more empowered and in control.” Those who internalised these strategies continued using the platform, creating a reinforcing cycle of improvement.

“The results may not generalise to less educated individuals,” the study noted. It added that the findings “support the potential for scalable, technology-driven interventions to help reduce years of cognitive decline while maximising brain performance across the lifespan.”

What do experts think?

Dr Atri Chatterjee, Associate Professor in the Department of Neurology at Vardhaman Mahavir Medical College and Safdarjung Hospital, Delhi, said the improvements observed in the study were not the result of brief online training alone, but of the cumulative effect of multiple measures working together to improve brain health. He cautioned that there were no shortcuts.

He added that “sustained cognitive effort improves cognitive reserve and preserves brain health.”

Dr Chatterjee said poor public literacy, low health literacy, and a lack of scientific rationalism remained major societal challenges in treating brain health as a public health priority, and these issues needed to be addressed alongside any intervention.

He noted that the findings appeared rational but said such studies should be replicated across different populations before stronger conclusions could be drawn.

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