A new observational study suggests that physically active older adults show slower cognitive decline and less brain Tau accumulation, with the strongest benefits seen at about 5,000 to 7,500 daily steps, even when preclinical Alzheimer’s indicators are held constant.

Possible mechanisms for the brain benefits include cognitive engagement during walking (navigation and interaction with surroundings), improved cardiovascular health, and the release of blood-borne growth and protective factors.

Researchers aim to analyze how changes in activity over time affect cognition and plan to use wearables to gather detailed data on exercise intensity and duration to optimize recommendations.

In Germany, Leqembi is available for very early-diagnosed patients since September, but it carries significant potential side effects and is not suitable for all individuals.

Authors caution that the study is observational and cannot prove causation, though results support clinical trials and reinforce lifestyle factors as protective brain health strategies.

The study was funded by NIH grants and foundations, with authors from Mass General Brigham and Harvard Aging Brain Study collaborators, and no competing interests declared.

Experts emphasize that findings are not definitive and call for randomized trials to separate exercise effects from confounding factors, while noting that regular physical activity has broad health benefits.

Additionally, the study notes that step counts were measured only at baseline and could be influenced by other factors like education, health, and lifestyle, preventing a causal conclusion.

Mindful, solitary walks may also support emotional processing and a calmer mindset that could improve task performance.

Reverse causation cannot be ruled out, and randomized trials are needed to establish causality.

Some researchers acknowledge reverse causality concerns, but argue that the lack of baseline cognitive association and other observations support a protective effect from exercise.