Fidget your way to vascular fitness

Fidgeting during prolonged times of sitting may actually help prevent arterial disease, according to a study published in the July 2016 issue of the American Journal of Physiology Heart and Circulatory Physiology.

“Many of us sit for hours at a time, whether it’s binge watching our favorite TV show or working at a computer,” said lead author Jaume Padilla, PhD, assistant professor, nutrition and exercise physiology, University of Missouri, Columbia, MO.

“We wanted to know whether a small amount of leg fidgeting could prevent a decline in leg vascular function caused by prolonged sitting. While we expected fidgeting to increase blood flow to the lower limbs, we were quite surprised to find this would be sufficient to prevent a decline in arterial function,” he added.

Thus, Dr. Padilla and colleagues conducted this study to assess whether the reductions in shear stress caused by sitting and thought to be associated with endothelial dysfunction may be mitigated by periodic leg movements. Shear stress is the friction of the flowing blood on the arterial wall, and is an important stimulus for vascular health.

They performed bilateral measurements of popliteal artery flow-mediated dilation (FMD) in 11 young, healthy subjects before and after they had sat for 3 hours, with one leg subjected to intermittent fidgeting of 1 minute on/4 minutes off, and keeping the other leg still. Subjects moved their feet an average of 250 times per minute.

In the “fidgety” leg, there was a significant increase in popliteal artery blood flow and shear rate, which at prefidgeting was 33.7 s^-1, to 222.7 s^-1 immediately after fidgeting (P < 0.001), with the effects tapering off in the ensuing minute.  

Fidgeting did not, however, change popliteal artery blood flow or shear rate of the leg that remained still, in which there were reductions in both blood flow and shear rate from presitting to 3-hour sitting (71.1 s^-1 to 20.2s^-1, respectively; P < 0.001).

After 3 hours of sitting, popliteal artery FMD was impaired in the leg that remained still, from a presitting rate of 4.5% to a postsitting rate of 1.6% (P=0.039). This rate improved, however, in the fidgeting leg from presit to postsit (3.7% to 6.6%, respectively; P=0.014).

“You should attempt to break up sitting time as much as possible by standing or walking,” concluded Dr. Padilla. “But if you’re stuck in a situation in which walking just isn’t an option, fidgeting can be a good alternative. Any movement is better than no movement.”

This study was supported by the National Institutes of Health (K01 HL-297 125503 and R21 DK-105368) and the Japan Society for the Promotion of Science (14J09537).