"The results of our study indicate that all physical activities including exercise as well as other activities such as cooking, washing the dishes, and cleaning are associated with a reduced risk of Alzheimer's disease. These results provide support for efforts to encourage all types of physical activity even in very old adults who might not be able to participate in formal exercise, but can still benefit from a more active lifestyle. This is the first study to use an objective measurement of physical activity in addition to self-reporting. This is important because people may not be able to remember the details correctly."
In order to track the overall amount of daily exercise and non-exercise physical activity, the researchers asked 716 people without dementia, who were on average 82 years old, from the from the Rush Memory and Aging Project to continuously wear an actigraph on their non-dominant wrist for ten days, which monitors all activity and records all exercise and non-exercise physical activity.
To measure memory and thinking abilities, all participants also underwent annual cognitive testing during the study period, in addition to self-reporting their physical and social activities. The Rush Memory and Aging Project is an ongoing, longitudinal community study of common chronic old age conditions.
71 participants developed Alzheimer's disease over an average follow-up period of 3.5 years. The findings demonstrated that those who were classed in the bottom 10% of daily physical activity had more than a two-fold (2.3 times) risk of developing Alzheimer's, as compared with those who were classed in the top 10% of daily activity.
The findings furthermore demonstrated that individuals in the bottom 10% of intense physical activity had a 2.8 times higher risk of developing the disease than those in the top percent of the intensity of physical activity.
"Since the actigraph was attached to the wrist, activities like cooking, washing the dishes, playing cards and even moving a wheelchair with a person's arms were beneficial. These are low-cost, easily accessible and side-effect free activities people can do at any age, including very old age, to possibly prevent Alzheimer's."
In view that by 2030, the number of Americans older than 65 years of age will double to 80 million, Buchman concluded:
"Our study shows that physical activity, which is an easily modifiable risk factor, is associated with cognitive decline and Alzheimer's disease. This has important public health consequences."