Cognitive and brain structural effects of long-term high-effort endurance exercise in older adults: are there measurable benefits?

Age-related decline in cognitive performance and brain structure can be offset by increased exercise. Little is known, however, about the cognitive and brain structural consequences of long-term high-effort endurance exercise. In a cross-sectional design, we recruited older adults who had been engaging in high-effort endurance exercise over at least twenty years, and compared their cognitive performance and brain structure with a non-sedentary control group similar in age, sex, education, IQ, depression levels, and other lifestyle factors. We hypothesized that long-term high-effort endurance exercise would protect against the age-related decline in memory, attention, and brain structure. Our findings, in contrast to previous studies, indicated that those participating in long-term high-effort endurance exercise, when compared without confounds to non-sedentary control volunteers, showed no differences on measures of speed of processing, executive function, incidental memory, episodic memory, working memory, or visual search. On measures of prospective memory, long-term exercisers performance suggested a self-imposed increase in effort, which did not impact on ability to complete the PM task. In complex attention tasks, they displayed a differential strategy to controls. Structurally, long-term exercisers only displayed higher diffuse axial diffusivity, an index of axonal integrity, than controls, but this did not correlate with any cognitive differences.