title: Physical Activity and White Matter Hyperintensities: A Systematic Review of Quantitative Studies.
abstract: OBJECTIVE
  White matter hyperintensities (WMH) are markers of brain white matter injury seen on magnetic resonance imaging. WMH increase with age and are associated with neuropsychiatric disorders. WMH progression can be slowed by controlling vascular risk factors in individuals with advanced disease. Since physical activity can decrease vascular risk factors, physical activity may slow the progression of WMH in individuals without advanced disease, thereby preventing neuropsychiatric disorders. The purpose of this systematic review was to examine the association between physical activity and WMH in individuals without advanced disease.
  
  
  METHODS
  Articles published in English through March 18, 2014 were searched using PubMed, Web of Science, Cochrane Library and EBSCOhost.
  
  
  RESULTS
  Six studies found that more physical activity was associated with less WMH, while 6 found no association. Physical activity is associated with less WMH in individuals without advanced disease when studies are longitudinal or take into consideration physical activity across the lifespan, have a younger sample of older adults, measure different types of physical activity beyond leisure or objectively measure fitness via V02max, measure WMH manually or semi-automatically, and control for risk factors associated with WMH.
  
  
  CONCLUSIONS
  More physical activity was associated with less white matter hyperintensities in individuals without advanced disease.
authors.affiliation: School of Nursing, 4123 Signe Skott Cooper Hall, 701 Highland Avenue, University of Wisconsin, Madison, WI 53705, 1 (608) 263-5268 Phone, 1 (608) 263-5323 Fax.
authors.forename: Elisa R
authors.initials: ER
authors.lastname: Torres
authors.affiliation: College of Letters and Science, 1305 Linden Drive, University of Wisconsin, Madison, WI 53706.
authors.forename: Emily F
authors.initials: EF
authors.lastname: Strack
authors.affiliation: College of Letters and Science, 1305 Linden Drive, University of Wisconsin, Madison, WI 53706.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Fernandez
authors.affiliation: College of Letters and Science, 1305 Linden Drive, University of Wisconsin, Madison, WI 53706.
authors.forename: Tyler A
authors.initials: TA
authors.lastname: Tumey
authors.affiliation: Department of Health Sciences Library, School of Medicine and Public Health, 2339 Health Sciences Learning Center, 750 Highland Avenue, Madison, WI 53705.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Hitchcock
keywords: exercise; leukoaraiosis; magnetic resonance imaging