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Exercise Reduces Brain Shrinkage

October 26 2012

by alex

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Researchers from the University of Edinburgh studied a group of almost 700 seniors over the age of seventy. They studied levels of physical activity which ranged from moving only for necessary housework to more strenuous forms of exercise such as keep-fit or taking part in competitive sports. They also recorded whether or not the participants took part in mentally stimulating activities such reading and participating in social groups. MRI scans were used to measure the volume of brain tissue and the volume and health of the brain’s white matter.

Their study revealed that those seniors that exercised regularly showed:
less brain shrinkage over just 3 years;
fewer “white matter lesions”;
more gray matter.
More social or mentally stimulating activities showed no effect on MRI findings.
Greater brain shrinkage is linked to problems with memory and thinking and the researchers say their findings suggest that exercise is potentially one important pathway to maintaining a healthy brain both in terms of size and reducing damage.

Neuroprotective lifestyles and the aging brain: Activity, atrophy, and white matter integrity
Alan J. Gow, Mark E. Bastin, Susana Muñoz Maniega, Maria C. Valdés Hernández, Zoe Morris, Catherine Murray,
Natalie A. Royle, John M. Starr, Ian J. Deary, Joanna M. Wardlaw,
Neurology October 23, 2012 vol. 79 no. 17 1802-1808
doi: 10.1212/WNL.0b013e3182703fd2

Abstract

Objectives: Increased participation in leisure and physical activities may be cognitively protective. Whether activity might protect the integrity of the brain’s white matter, or reduce atrophy and white matter lesion (WML) load, was examined in the Lothian Birth Cohort 1936 (n = 691), a longitudinal study of aging.

Methods: Associations are presented between self-reported leisure and physical activity at age 70 years and structural brain biomarkers at 73 years. For white matter integrity, principal components analysis of 12 major tracts produced general factors for fractional anisotropy (FA) and mean diffusivity. Atrophy, gray and normal-appearing white matter (NAWM) volumes, and WML load were assessed using computational image processing methods; atrophy and WML were also assessed visually.

Results: A higher level of physical activity was associated with higher FA, larger gray and NAWM volumes, less atrophy, and lower WML load. The physical activity associations with atrophy, gray matter, and WML remained significant after adjustment for covariates, including age, social class, and health status. For example, physical activity (standardized β = −0.09, nonstandardized β = −0.09, p = 0.029) and stroke (standardized β = 0.18, nonstandardized β = 0.69, p = 0.003) each had an independent effect on rated WML load. Leisure activity was associated with NAWM volume, but was nonsignificant after including covariates.

Conclusions: In this large, narrow-age sample of adults in their 70s, physical activity was associated with less atrophy and WML. Its role as a potential neuroprotective factor is supported; however, the direction of causation is unclear from this observational study.