According to a joint study between the Group Health Cooperative and the University of Washington, the very first signs of dementia and Alzheimer's disease, may well be physical, rather than mental.
The study led by Eric B. Larson, MD, MPH, director of Group Health Center for Health Studies, followed 2,288 Group Health members age 65 and older for six years.
At the outset none showed any signs of dementia or Alzheimer's disease; they were assessed by the research team every two years, using a variety of tests, for both physical and mental functioning.
After six years it was found that 319 participants had developed dementia, including 221 with Alzheimer's disease.
The researchers say the participants whose physical function was higher at the start of the study were three times less likely to develop dementia than were those whose physical function was lower.
Dr. Larson says they had expected the earliest signs of dementia would be subtle cognitive changes and were surprised to find that physical changes can precede declines in thinking.
The implication he says is that what is considered to be a brain disease may be intimately connected to physical fitness.
The researchers say that they found the first indicators of future dementia appeared to be problems with walking and balance and a weak handgrip may be a later sign of the development of dementia in older people.
Recent research has also found that when people exercised regularly, they were less likely to develop dementia, including Alzheimer's disease but does not clearly explain the association.
This latest study suggests that regular exercise may help stave off dementia by improving and maintaining physical conditioning.