here is the link

http://www.ncbi.nlm.nih.gov/pubmed/20150596

As the removed post wrongly attributed this article (which is not a study but rather a speech/address) to an entirely different person than the one who wrote it (and one who, as a leading expert in Alzheimer's research, would definitely not endorse the sweeping generalizations in it), it will remain hidden.

Please take care with attribution. In this instance there are 2 very different people with same last name and first initial (but different first names) involved. Partiucularly when citing claims that are not backed by (or go beyond) c=research to date, mis-attributing is a serious error bordering in libel.

here is a study on links between exercise and cognitive impairment/Alzheimer

http://www.ncbi.nlm.nih.gov/pubmed/20065132

Yes, it is well known that exercise is good for cognitive function. In niormal people and also those with cognitive impairment.

It does not, however, prevent nor cure AD though it does improve the functioning of people with it (if you can get them to do it!)