Short walks may reverse damage from prolonged sitting, study says

It’s no secret sitting behind a desk all day can be bad for your health.

In fact, prolonged periods of sitting have been associated with higher cholesterol levels and greater waist circumference which can lead to cardiovascular and metabolic disease.

But a new study has found that taking a 5-minute walk for each hour you sit could reverse the damage to leg arteries and reduce the risk for heart disease.

Researchers at Indiana University looked at 11 non-obese, healthy men ages 20-35 who sat for three hours without moving their legs. They used a blood pressure cuff and ultrasound technology to measure femoral artery function at the beginning of the study and again at the one-, two- and three-hour marks.

Study authors found that during a 3-hour period, the function of the femoral artery was decreased by as much as 50 percent after just one hour of sitting. But study participants who walked for five minutes during each hour of sitting did not experience a drop in arterial function suggesting that the increase in muscle activity and blood flow was beneficial.

"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, a postdoctoral researcher at Oregon Health & Science University, who led the study as a doctoral candidate at IU's School of Public Health-Bloomington said in a release. "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."

In the second trial, the men walked on a treadmill for five minutes at 2 mph -- a significantly slower speed than those in the first trial. When their femoral artery function was measured at the 30-minute, 1.5-hour and 2.5-hour marks they showed the same level of function.

"American adults sit for approximately eight hours a day," he said. "The impairment in endothelial function is significant after just one hour of sitting. It is interesting to see that light physical activity can help in preventing this impairment."

The study will be published in Medicine & Science in Sports & Exercise.