Physical activity and white matter hyperintensities: A systematic review of quantitative studies

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. Articles published in English through March 18, 2014 were searched using PubMed, Web of Science, Cochrane Library and EBSCOhost. 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 VO2 max, measure WMH manually or semi-automatically, and control for risk factors associated with WMH. More physical activity was associated with less white matter hyperintensities in individuals without advanced disease.