title: Life-long aerobic exercise preserved baseline cerebral blood flow but reduced vascular reactivity to CO2.
abstract: OBJECTIVE
  To examine the potential benefits of life-long aerobic exercise on brain health, in particular cerebrovascular function.
  
  
  METHODS
  Ten Masters athletes (MA) (seven males, three females; 74.5 ± 5.8 years) and 10 sedentary elderly individuals (SE) (eight males, two females; 75.4 ± 5.6 years) were recruited and baseline cerebral blood flow (CBF) and cerebral vascular reactivity (CVR) to CO2 were measured on a 3T MRI scanner. Nine sedentary young subjects were also recruited to serve as a control group to verify the age effect.
  
  
  RESULTS
  When compared to the SE group, MA showed higher CBF in posterior cingulate cortex/precuneus, which are key regions of the default-mode-network and are known to be highly sensitive to age and dementia. CVR in the MA brains were paradoxically lower than that in SE. This effect was present throughout the brain. Within the MA group, individuals with higher VO2max had an even lower CVR, suggesting a dose-response relationship.
  
  
  CONCLUSIONS
  Life-long aerobic exercise preserved blood supply in the brain's default-mode-network against age-related degradation. On the other hand, its impact on the cerebral vascular system seems to be characterized by a dampening of CO2 reactivity, possibly because of desensitization effects due to a higher lifetime exposure.
authors.affiliation: Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA; Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, Texas / UT Arlington, Arlington, Texas, USA.
authors.forename: Binu P
authors.initials: BP
authors.lastname: Thomas
authors.forename: Uma S
authors.initials: US
authors.lastname: Yezhuvath
authors.forename: Benjamin Y
authors.initials: BY
authors.lastname: Tseng
authors.forename: Peiying
authors.initials: P
authors.lastname: Liu
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Levine
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Hanzhang
authors.initials: H
authors.lastname: Lu
mesh_terms: D000375:Aging / Q000187:drug effects / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D002245:Carbon Dioxide / Q000008:administration & dosage; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D057185:Sedentary Behavior; D013177:Sports / Q000502:physiology*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
keywords: BOLD MRI; CO2; arterial-spin-labeling; cerebral blood flow; cerebral vascular reactivity; masters athletes