Reacción a "Moderate exercise may slow cognitive decline caused by preclinical Alzheimer's disease"

This research provides strong evidence that moderate levels of physical activity are associated with slower progression of the earliest stages of Alzheimer’s disease, and that this is linked to slower accumulation of tau protein, which is an important cause of brain cell loss.

With this type of observational study, it is always hard to be sure whether the physical activity is actually the thing causing the observed difference. The authors do a good job of trying to disentangle this, but we cannot be certain whether the people doing more exercise are healthier in other ways, nor whether the development of Alzheimer’s disease changes are influencing activity levels (reverse causality). We also cannot be sure that it is physical activity during this period in later life that makes the difference, or whether those who are more active now have been more active for decades and that the benefits accrue in the much longer term.

Nevertheless, this study does add to a wealth of evidence suggesting that regular physical activity is good for your brain as well as all of the other physical benefits it brings, and I would have no hesitation in encouraging people to aim for a daily step goal.