title: White matter integrity in physically fit older adults.
abstract: BACKGROUND
  White matter (WM) integrity declines with normal aging. Physical activity may attenuate age-related WM integrity changes and improve cognitive function. This study examined brain WM integrity in Masters athletes who have engaged in life-long aerobic exercise training. We tested the hypothesis that life-long aerobic training is associated with improved brain WM integrity in older adults.
  
  
  METHODS
  Ten Masters athletes (3 females, age=72.2 ± 5.3 years, endurance training >15 years) and 10 sedentary older adults similar in age and educational level (2 females, age=74.5 ± 4.3 years) participated. MRI fluid-attenuated-inversion-recovery (FLAIR) images were acquired to assess white matter hyperintensities (WMH) volume. Diffusion tensor imaging (DTI) was performed to evaluate the WM microstructural integrity with a DTI-derived metric, fractional anisotropy (FA) and mean diffusivity (MD).
  
  
  RESULTS
  After normalization to whole-brain volume, Masters athletes showed an 83% reduction in deep WMH volume relative to their sedentary counterparts (0.05 ± 0.05% vs. 0.29 ± 0.29%, p<0.05). In addition, we found an inverse relationship between aerobic fitness (VO2max) and deep WMH volume (r=-0.78, p<0.001). Using TBSS, Masters athletes showed higher FA values in the right superior corona radiata (SCR), both sides of superior longitudinal fasciculus (SLF), right inferior fronto-occipital fasciculus (IFO), and left inferior longitudinal fasciculus (ILF). In addition, Masters athletes also showed lower MD values in the left posterior thalamic radiation (PTR) and left cingulum hippocampus.
  
  
  CONCLUSIONS
  These findings suggest that life-long exercise is associated with reduced WMH and may preserve WM fiber microstructural integrity related to motor control and coordination in older adults.
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.
authors.forename: B Y
authors.initials: BY
authors.lastname: Tseng
authors.forename: T
authors.initials: T
authors.lastname: Gundapuneedi
authors.forename: M A
authors.initials: MA
authors.lastname: Khan
authors.forename: R
authors.initials: R
authors.lastname: Diaz-Arrastia
authors.forename: B D
authors.initials: BD
authors.lastname: Levine
authors.forename: H
authors.initials: H
authors.lastname: Lu
authors.forename: H
authors.initials: H
authors.lastname: Huang
authors.forename: R
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D056352:Athletes; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D010809:Physical Fitness / Q000502:physiology*
keywords: Aging; Exercise; MRI; Plasticity; White matter disease