The influence of physical fitness on automatic and effortful memory changes in aging.

A cross-sectional study was carried out in order to determine the influence of cardiovascular fitness on age-related declines in cognitive performance. Forty-eight volunteers were divided into Young (n = 13, 18-27 years), Middle-Aged (n = 22, 60-65 years) and Old (n = 13, 65-88 years) groups and tested on a battery of cardiovascular, pulmonary, hemodynamic, and biochemical tests in order to assess physical fitness. Cognitive performance was evaluated by a variety of memory tasks distributed along an automatic-to-effortful processing continuum. Memory for location and frequency of occurrence were selected as representative of automatic processing, whereas, an auditory free-recall task was selected as representative of effortful processing. Age-related performance declines were observed for the free-recall task, but no such age-dependent association was observed for frequency and location memory. With regard to the influence of physical fitness; the Middle-Aged and Older participants were divided into High and Low Fitness groups and significant differences were observed between these groups for the effortful but not the automatic memory tasks. These data suggest that the relationship between physical fitness and cognitive performance in old age is task dependent. Furthermore, the apparent prophylactic effects of physical fitness on effortful memory, do not appear to extend to cognitive tasks requiring less effortful processing.