Most of us, by now, are familiar with the concept that sitting for lengthy periods of time can be harmful to our health. Too much sitting can lead to an increased risk of cardiovascular problems, obesity, high cholesterol and other chronic health conditions. When we sit for too long, our muscles stop contracting and blood will settle in our legs instead of being effectively pumped throughout our bodies. As a result, damage to the endothelial function of the arteries can occur. This means that the lining of the blood vessels becomes less able to dilate and contract.

A recent study conducted at Indiana University in the United States shows some promise. Results showed that those who take at least three 5-minute walks per day, can reverse the negative effects of sitting for 3 hours.

Researchers examined 12 different non-obese men and divided them into two groups. One group remained in a sitting position for 3 hours without moving their legs or feet, and the second group also sat at a desk but took three 5-minute slow walks throughout the course of each day, on a treadmill. The walking group kept a 3.2km per hour pace (2mph), and the walks occurred at 30 minutes, 90 minutes and 2.5 hours into the sitting period.

At the end of the three hour period, scientists used ultrasound technology to examine the inner lining of the femoral arteries (the large artery in the thigh, the main blood supply to the leg). In the first group, who sat for the entire time, decreased dilation was noted—up to 50% less. The walking group experienced no decrease in dilation.

Despite the small sample size for this study, the results were deemed statistically significant enough to be published in Medicine & Science in Sports & Exercise.

Lead author, Saurabh Thosar, stated, "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. 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."

Although this study was fairly small, the results are promising because they show that the harmful effects of sitting can be reversed. Says Thosar, “American adults sit for approximately eight hours a day. 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."

Make sure that short walks are a part of your day if you are required to sit for long periods of time!