"This study not only tells us that there is a benefit to being highly fit, it pinpoints where in the brain it matters for postmenopausal women who have been using the two strategies," said lead author Kirk I. Erickson, a postdoctoral researcher at the Beckman Institute for Advanced Science and Technology at Illinois.

The study appeared online this month in advance of regular publication in the journal Neurobiology of Aging. By using magnetic resonance imaging and voxel-based morphometry (VBM), researchers documented the combined effects on specific areas of the brain based on fitness of short- and long-term users of hormone therapy.

Researchers also looked at how well 54 postmenopausal women performed on a computerized version of the Wisconsin Card Sort Test, in which constantly changing rules challenge memory, inhibition and task-switching abilities known as executive functions. The women were divided into groups based on use or non-use and duration of hormone therapy and existing fitness levels.

"We found that higher fitness levels enhance the effects of shorter durations of hormone treatment and offset the declines associated with long-term use," said Arthur F. Kramer, a Beckman researcher and psychology professor. "It may be that a combination of HRT and exercise boosts both cognition and brain structure of older women."

Participants ranged in age from 58 to 80, with a mean age of 70. Hormone status and duration of use were assessed based on their self-reports, and aerobic fitness was measured by monitoring respiration, heart rate and blood pressure during a treadmill test.

MRI images of the participants' brains were taken, segmented into 3-D maps and analyzed by VBM, which allow
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Contact: Jim Barlow, Life Sciences Editor
jebarlow@uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
24-Jan-2006