Australian researchers conducted a randomised controlled trial to see whether physical activity intervention would reduce the rate of cognitive decline among 138 patients aged over 50 at increased risk of dementia.
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 programme of physical activity.
Those in the intervention group were recommended to perform at least 150 minutes of moderate-intensity physical activity per week in three 50-minute sessions, with walking the most common exercise.
Cognitive function was assessed with the Alzheimer Disease Assessment Scale – Cognitive Subscale (ADAS-Cog) over 18 months.
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 and lower clinical dementia rating scores.
Authors wrote: ‘To our knowledge, this trial is the first to demonstrate that exercise improves cognitive function in older adults with subjective and objective mild cognitive impairment.’
Journal of the American Medical Association (2008) 300:1027-1037