Growing evidence suggests that physical
exercise may be protective against cognitive
impairment and decline. A prospective study
of a representative rural community sample
(N = 1,146) aged 65+ years examined
self-reported exercise habits and measured
global cognitive function using the
Mini-Mental State Examination (MMSE). A
composite variable "exercise level"
combining type, frequency, and duration of
exercise was created with three levels:
"high exercise" (aerobic exercise of > or =
30 minute duration > or = 3 times a week),
"low exercise" (all other exercise groups),
and "no exercise." Cognitive decline was
defined as being in the 90 percentile of
decline in this cohort, ie, declining by 3
or more MMSE points during the 2-year
interval between two assessments. In a
multiple regression model, high exercise
level at the baseline assessment was
negatively associated with, ie, was
protective against, being in the group with
the greatest amount of decline at the
follow-up assessment, after adjusting for
likely confounders (odds ratio = 0.39; 95%
confidence interval, 0.19, 0.78). When high
exercise was redefined using frequency as >
or = 5 days per week as the threshold, as
per the Surgeon General's guidelines, both
low exercise and high exercise were
negatively associated with cognitive
decline. Exercise may have implications for
prevention of cognitive decline.