Wednesday, September 10, 2014 Light-Intensity Short Walks Can Prevent LE Vascular Damage Caused by Sitting Long bouts of sitting can have serious effects on blood flow that could increase risk of cardiovascular disease, but a new study proposes that lower extremity vascular damage can be prevented by walking as few as 5 minutes every hour—and not even at a particularly fast pace. In a study e-published ahead of print in Medicine and Science in Sports and Exercise (abstract only available for free), researchers from Indiana University monitored the ways in which the superficial femoral artery reacted to 3 hours of sitting without leg movement, and compared those results with study participants who took 5-minute walks at 2 miles per hour every hour. What they found was that prolonged sitting does lead to a "significant impairment" in endothelial function, but that the short walks prevented the damage from taking place altogether. The study was limited to 12 nonsmoking men in their 20s who did not meet the physical activity guidelines of the Centers for Disease Control and Prevention, and were not taking any anti-hypertensive, lipid lowering, or anti-diabetic medications. Assessments were based on measurements of mean shear rates and flow-mediated dilation of the superficial femoral artery just above the knee. "Uninterrupted sitting leads to a progressive decline in antegrade and mean shear rate and corresponding impairment in endothelial function," authors write. "We can hypothesize that repeated bouts of prolonged sitting may contribute to vascular aging, at least in the lower extremities." But walking made all the difference. "Even this very light-intensity physical activity prevented the decline … and may explain the protective effect against sitting-induced impairment," they write. "We believe our observations further the argument to have structured public health guidelines on limiting sitting time." The study was featured in both the Washington Post and United Press International. Earlier research on the cardiovascular risks of prolonged sitting has been reported in Mayo Clinic Proceedings (.pdf) and elsewhere. Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.