Adults with memory problems who participated in a home-based physical activity program experienced a modest improvement in cognitive function, compared to those who did not participate in the program, according to a study published in JAMA.
As the world population ages, the number of older adults living with Alzheimer's disease is estimated to increase from the current 26.6 million to 106.2 million by 2050. "If illness onset could be delayed by 12 months, 9.2 million fewer cases of Alzheimer's disease would occur worldwide. For this reason, attempts have been made to identify individuals who are at increased risk of Alzheimer's disease and to test interventions that might delay the progression of prodromal symptoms (early nonspecific symptom, or set of symptoms) to full-blown dementia," the authors write.
Nicola T Lautenschlager of the University of Melbourne, Australia, and colleagues conducted a randomised controlled trial to test whether a physical activity intervention would reduce the rate of cognitive decline among 138 adults age 50 years and older at increased risk of dementia. The participants, who reported memory problems but did not meet criteria for dementia, were randomly allocated to an education and usual care group or to a 24-week home-based program of physical activity.
The aim of the intervention was to encourage participants to perform at least 150 minutes of moderate-intensity physical activity per week, which participants were asked to complete in three 50-minute sessions each week. The most frequently recommended type of activity was walking.
Cognitive function was assessed with the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-Cog; a measuring tool that consists of a number of cognitive tests) over 18 months.
The researchers found that by study end, participants in the exercise group had better ADAS-Cog scores and delayed recall than those in the usual care control group. Participants in the physical activity group also had lower Clinical Dementia Rating scores than those in the usual care group.
"Unlike medication, which was found to have no significant effect on mild cognitive impairment at 36 months, physical activity has the advantage of health benefits that are not confined to cognitive function alone, as suggested by findings on depression, quality of life, falls, cardiovascular function, and disability," the authors write.