With increasingly sedentary lifestyles, Americans have seen a rise in obesity and diabetes, as well as increased risks of cardiovascular disease, cancer and early deaths. Australian researchers found in 2012 that extended sitting constricts blood vessels and blood flow in the legs and negatively affects metabolism, regardless of one’s weight or overall time spent exercising. This month, however, researchers at Indiana University reported that walking breaks of just 5 minutes per hour sitting might reverse these negative side effects of being sedentary.
In the most recent study at Indiana University’s School of Public Health-Bloomington, researchers had male subjects sit for three hours and measured the functionality of the femoral artery. After sitting for just one hour, the subjects experienced decreased expansion of the main artery by as much as 50 percent as a result of diminished blood flow to the legs.
The men then walked on a treadmill for 5 minutes on the hour after an initial 30 minutes of sitting. When subjects walked for five minutes for each hour they sat, there was no decreased function in the arteries.
The research was published in the journal Medicine & Science in Sports & Exercise on Sept. 8.
“American adults sit for approximately eight hours a day,” study author Saurabh Thosar, now a postdoctoral researcher at Oregon Health & Science University, said in a news release.
When sitting for extended periods of time, the lack of adequate contraction of leg muscles causes decreased blood flow, allowing blood to pool in the legs.
While Thosar noted a plethora of epidemiological evidence linking sitting to several chronic disease, he said that experimental evidence was lacking in showing that breaking up periods of sitting had cardiovascular benefits. In the Indiana University study, he said,”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.”
Lead author of the 2012 study from the University of Sydney, Hidde van der Ploeg, told Reuters, “When you are standing or walking, your leg muscles are constantly working, which helps to clear blood glucose and blood fats from the blood stream. If you are sitting this is not happening because the muscles are not active.”
In the modern era, nearly everything we need is only a car ride or click of a computer key away. The vast majority of us spend eight hours or more hours a day sitting at a desk, staring at the computer screen, five days a week. When we come home, too many of us, head immediately to the couch where we sit in front of the television for another several hours. While our hunter-gather ancestors broke up anywhere from 6 to 16 kilometers of daily walking throughout the day, Mark Sisson of Mark’s Daily Apple writes, the walking of modern man, if it occurs at all, is “lumped together in a single uninterrupted session on the treadmill after work.”
So take a break from your computer—after reading this article—and take a brisk walk to get your body moving and your blood flowing. Head outside for a stroll, or better yet—climb some stairs. Sisson suggests that walking on uneven terrain is “far better at improving and maintaining balance, physical fitness, and metabolic health,” as it expends more energy than walking on flat terrain.