Move it, use it, and you are less likely to lose it. Physical activity — even in small amounts — is a factor in slowing the process of the cognitive deficits associated with Alzheimer's disease. This has been found to hold true even for those genetically at risk for Alzheimer's disease.

Factors related to the APOE gene impact the risk for Alzheimer's disease, and everyone inherits a version of APOE from each parent, having two copies of some form of APOE. However, of the three common versions — APOE-e2, APOE-e3 and APOE-e4 — APOE-e4 is considered to be a risk for developing Alzheimer's disease.

If you have one copy of APOE-e4, your risk for Alzheimer's disease is increased compared to having no copies. If you inherit two copies of APOE-e4, the risk for Alzheimer’s disease is even greater.

In a study using magnetic resonance imaging looking a the size of the hippocampus (the region of the brain processing memory), researchers found the size was influenced by exercise. The researchers had divided a group of healthy adults with no signs of cognitive dysfunction into four categories:

  1. low APOE risk and physically active
  2. low APOE risk and not physically active
  3. high APOE risk and physically active
  4. high APOE risk and not physically active

After following the groups for 18 months, they found that the brain hippocampal volume in the high-risk and low-physical activity group had decreased by 3 percent, but the hippocampal volume had remained unchanged in the other three categories. The researchers concluded that exercise may be of benefit to those at risk for Alzheimer's disease.

Other studies have found that a higher rate of total physical activity is associated with a lower rate of cognitive decline in Alzheimer's disease. An aerobic activity lasting 40 minutes at least three times a week is suggested as a means to minimize the risks of Alzheimer's disease related cognitive decline.

Exercise was a prominent topic during the Alzheimer's Association International Conference (AAIC) held in July in Copenhagen, Denmark. The AAIC brings together top researchers in the field of dementia in order to engage a multidisciplinary international exchange of ideas.

There were more than 20 presentations covering physical activity. Topics included exercise related to diabetes and cardiovascular health associated with Alzheimer's disease risk, as well as the benefits of activities such as yoga and tai chi.

With 5 million Americans already having Alzheimer's disease — and this number is projected to triple by the year 2050 — any means to slow down or prevent the progression of Alzheimer's disease is of value.

Increasing the quality and quantity of physical activity is proving to be a cost-effective and healthy means to do so. We all need to get moving on this.