title: Aerobic fitness reduces brain tissue loss in aging humans.
abstract: BACKGROUND
  The human brain gradually loses tissue from the third decade of life onward, with concomitant declines in cognitive performance. Given the projected rapid growth in aged populations, and the staggering costs associated with geriatric care, identifying mechanisms that may reduce or reverse cerebral deterioration is rapidly emerging as an important public health goal. Previous research has demonstrated that aerobic fitness training improves cognitive function in older adults and can improve brain health in aging laboratory animals, suggesting that aerobic fitness may provide a mechanism to improve cerebral health in aging humans. We examined the relationship between aerobic fitness and in vivo brain tissue density in an older adult population, using voxel-based morphometric techniques.
  
  
  METHODS
  We acquired high-resolution magnetic resonance imaging scans from 55 older adults. These images were segmented into gray and white matter maps, registered into stereotaxic space, and examined for systematic variation in tissue density as a function of age, aerobic fitness, and a number of other health markers.
  
  
  RESULTS
  Consistent with previous studies of aging and brain volume, we found robust declines in tissue densities as a function of age in the frontal, parietal, and temporal cortices. More importantly, we found that losses in these areas were substantially reduced as a function of cardiovascular fitness, even when we statistically controlled for other moderator variables.
  
  
  CONCLUSIONS
  These findings extend the scope of beneficial effects of aerobic exercise beyond cardiovascular health, and they suggest a strong solid biological basis for the benefits of exercise on the brain health of older adults.
authors.affiliation: Beckman Institute, University of Illinois, Urbana 61801, USA.
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Colcombe
authors.forename: Kirk I
authors.initials: KI
authors.lastname: Erickson
authors.forename: Naftali
authors.initials: N
authors.lastname: Raz
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Webb
authors.forename: Neal J
authors.initials: NJ
authors.lastname: Cohen
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology*; D003072:Cognition Disorders / Q000453:epidemiology / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008019:Life Style; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019150:Neuroaxonal Dystrophies / Q000453:epidemiology / Q000473:pathology; D010487:Periaqueductal Gray / Q000473:pathology*; D010809:Physical Fitness / Q000502:physiology*; D011336:Probability