Jul 15, 2012

Moderate Walking May Grow Brain Region Related to Memory

The researchers found that, in this study group, one year of exercise training increased the size of the hippocampus by two percent. Shrinking of the hippocampus is a characteristic of Alzheimer's disease.

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According to Kirk Erickson, PhD, of the University of Pittsburgh,
"There is growing interest in lifestyle factors and interventions that enhance the cognitive vitality of older adults and reduce the risk for cognitive impairment.
However, very little is understood regarding the molecular processes that contribute to enhanced brain health with exercise, or the impact that greater brain volume has on cognitive function."

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Moderate walking may grow brain region related to memory; increase nerve growth factor

Erickson and colleagues randomized 120 older adults without dementia who have been sedentary for the previous six months to a moderate intensity walking group or a stretching-toning group for one year. MRI was used to measure the size of a brain region associated with memory, known as the hippocampus, both before and after the exercise intervention. Blood was drawn to measure concentrations of brain-derived neurotrophic factor (BDNF), and a cognitive testing battery was conducted before and after the intervention.

The researchers found that, in this study group, one year of exercise training increased the size of the hippocampus by two percent (2%) in the walking group compared to the stretching-toning group. (Significant shrinking of the hippocampus is characteristic of Alzheimer's disease.) The increase in hippocampal volume was correlated with similar changes in BDNF.

"Our findings suggest that the aging brain remains modifiable, and that sedentary older adults can benefit from starting a moderate walking regimen," Erickson said.

The Influence of an Aerobic Exercise Intervention on Brain Volume in Late Adulthood

Kirk Erickson1, Andrea M. Weinstein1, Timothy D. Verstynen1, Michelle W. Voss2, Ruchika Shaurya Prakash3, Jeffrey Woods2, Edward McAuley2, Arthur F. Kramer2
1University of Pittsburgh, Pittsburgh, Pennsylvania, United States; 2University of Illinois, Champaign, Illinois, United States; 3Ohio State University, Columbus, Ohio, United States
Presenting author e-mail: kiericks@pitt.edu

Background: There is growing interest in lifestyle factors and interventions that enhance the cognitive vitality of older adults and reduce the risk for cognitive impairment. Aerobic exercise is a promising method for enhancing cognitive and brain health throughout the lifespan. However, very little is understood regarding the molecular processes in humans that contribute to enhanced brain health with exercise or the impact that greater brain volume has on cognitive function.

Methods:  One-hundred twenty older adults without dementia were randomized to a moderate intensity walking group or to a stretching-toning control group for one-year. Magnetic resonance imaging (MRI) was used to assess cortical and hippocampal volume both before and after the intervention. Serum was obtained to assess concentrations of brain-derived neurotrophic factor (BDNF) and a cognitive battery was conducted before and after the intervention.

Results: One year of aerobic exercise training increased the size of the anterior hippocampus by 2% in the exercise group as compared to the stretching-toning control group. These changes in hippocampal volume were positively correlated with changes in serum levels of BDNF. In addition, higher cardiorespiratory fitness was associated with greater volume of the prefrontal cortex, which mediated the link between fitness and cognitive performance.

Conclusions: Overall, these findings suggest that the aging brain remains modifiable and that older adults who have been sedentary for at least 6-months can still benefit from starting a moderate walking regimen. Increases in hippocampal and prefrontal cortex volume are linked to improved cognitive function and increased levels of serum BDNF.

Source: Kirk Erickson, et al. The influence of an aerobic exercise intervention on brain volume in late adulthood. (Funder: National Institute on Aging)

About AAIC®
The Alzheimer's Association International Conference® (AAIC) is the world's largest conference of its kind, bringing together researchers from around the world to report and discuss groundbreaking research and information on the cause, diagnosis, treatment and prevention of Alzheimer's disease and related disorders. As a part of the Alzheimer's Association's research program, AAIC serves as a catalyst for generating new knowledge about dementia and fostering a vital, collegial research community.


Original content Bob DeMarco, the Alzheimer's Reading Room