Short Walking Breaks May Reverse Negative Effects of Prolonged SittingBy J Baulkman
Short walking breaks could reverse the adverse effects of prolonged sitting, according to a recent study.
Researchers from Indiana University found that three easy 5 minute walks can reverse harm caused to leg arteries during three hours of prolonged sitting. The study is the first experimental evidence of these effects.
"There is plenty of epidemiological evidence linking sitting time to various chronic diseases and linking breaking sitting time to beneficial cardiovascular effects, but there is very little experimental evidence," Saurabh Thosar, leader of the study, said in a statement. "We have shown that prolonged sitting impairs endothelial function, which is an early marker of cardiovascular disease, and that breaking sitting time prevents the decline in that function."
Sitting for long periods of time, like many people do daily at their jobs, is associated with risk factors such as higher cholesterol levels and greater waist circumference that can lead to cardiovascular and metabolic disease, researchers said. When people sit, slack muscles do not contract to effectively pump blood to the heart. Blood can pool in the legs and affect the endothelial function of arteries, or the ability of blood vessels to expand from increased blood flow.
For the study, researchers conducted two trials.
The first trial involved 11 non-obese healthy men between the ages of 20-35 who participated in two randomized trials. In one trial they sat for three hours without moving their legs. Researchers used a blood pressure cuff and ultrasound technology to measure the functionality of the femoral artery at baseline and again at the one-, two- and three-hour mark.
In the second trial, the men sat during a three-hour period but also walked on a treadmill for 5 minutes at a speed of 2 mph at the 30-minute mark, 1.5-hour mark and 2.5-hour mark. Researchers measured the functionality of the femoral artery at the same intervals as in the other trial.
The research team was able to demonstrate that during a three-hour period, the flow-mediated dilation, or the expansion of the arteries as a result of increased blood flow, of the main artery in the legs was impaired by as much as 50 percent after just one hour. The study participants who walked for five minutes each hour of sitting saw their arterial function stay the same -- it did not drop throughout the three-hour period.
Thosar said it is likely that the increase in muscle activity and blood flow accounts for this.
The findings were recently published in the journal Medicine & Science in Sports & Exercise.