The influence of aerobic fitness on cerebral white matter integrity and cognitive function in older adults: results of a one-year exercise intervention

Cerebral white matter degeneration occurs with increasing age and is associated with declining cognitive function. Given the expected rise in the number and proportion of older adults in the United States, it is imperative to identify lifestyle factors that can counteract the deleterious effects of aging. Research has shown that cardiovascular fitness and exercise are effective as protective, even restorative, agents against cognitive and neurobiological impairments in older adults. In this study, we investigated whether the beneficial impact of aerobic fitness would extend to white matter integrity in the context of a one-year exercise intervention. Further, we examined the pattern of diffusivity changes to better understand the biological mechanisms underlying the observed differences. Finally, we tested whether white matter integrity mediated the fitness-associated improvements in cognitive performance. Using a region-of-interest approach on diffusion tensor images in 70 older adults, we examined longitudinal differences in fractional anisotropy, radial diffusivity and axial diffusivity within the prefrontal, parietal, occipital and temporal lobes. Our results indicate that improved cardiovascular fitness is associated with superior white matter integrity particularly in prefrontal and parietal brain regions, and that fractional anisotropy and radial diffusivity exhibit an overlapping pattern of distribution. In addition, we found a trend towards increased parietal white matter integrity partially mediating the relationship between improved aerobic fitness and enhanced short-term memory performance. We provide the first evidence for cerebral white matter integrity as one neurobiological mechanism explaining the beneficial influence of aerobic fitness on cognitive performance in older adults.

Name thesis:degree_name

M.A.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Psychology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Heo, Susie

Contributors dc:contributor

• Kramer, Arthur F.

• Diffusion tensor imaging
• Anisotropy
• Cerebrum
• Brain
• Cognition
• Physical fitness
• Aging
• Intervention studies

Statement dc:rights

• Copyright 2010 Susie Heo

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/16883

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/16883