Sitting at a desk all day – or on the couch all weekend – is not a good idea. Getting up and walking around, even for brief breaks, helps with clear both the head and the circulation, which will help offset the harm of sitting still too long.
Taking short but frequent walks, even for five-minutes around the building or floor at work, helps improve blood flow and, long-term, overall health, according to a recent Indiana University (IU) study published Monday is the journal Medicine & Science in Sports & Exercise.
Sitting for long periods of time can cause the blood in the legs to pool. This occurs because leg muscles do not pump blood to the heart as effectively when inactive and sedentary for a while. Prolonged stretches of sitting can impact arteries in legs and blood flow can become impaired. Nerve impulses from the brain to extremities are also impacted. Sit too long and the effects take longer to wear off. (One example is the sensation of a foot falling asleep.)
Many American adults sit for at least eight hours a day. The study’s author Saurabh Thosar, who is a postdoctoral researcher at Oregon Health & Science University, noted that the impairment in function people suffer could be “significant after just one hour of sitting.” Thosar, who was a IU School of Public Health-Bloomington doctoral candidate during the study, pointed out that the researchers found it interesting that light physical activity could make a difference in preventing any deficiency in the blood flow.
The research study involved examining what happens to healthy men after three hours of sitting. The 11 participants were healthy, non-obese men, ranging in age from 20 to 35 years old.
During the first session, the men sat without moving their legs for the three-hour period. At the onset of the study and hourly afterwards, their femoral artery function was measured with ultrasound technology and a blood pressure cuff.
For the second session, the men also sat for three hours, but they also took breaks to walk on a treadmill for five minutes at the 30-minute, 1.5-hour and 2.5-hour marks. The group kept a slow, 2 miles per hour pace when walking. Their femoral artery function was again assessed with a blood pressure cuff and ultrasound.
Based on the observations and data gathered, the researchers found that the leg arteries could only expand by as much as 50 percent once the men had been sitting for one hour. However, when the men took brief walking breaks to offset each hour they had spent sitting, there was no reduction or harm in artery function during the three-hour period as seen in people who sat too long.
The study team concluded that the five minutes of exercise increased the muscle activity and blood flow enough to offset the negative effect sitting so long had on them. Thosar reported that they determined that prolonged periods of sitting impairs arterial (endothelial) function in the legs, which can normally be an early marker of heart disease. However, taking brief walking breaks offsets and prevents the harm to and decline in arterial function that can be caused by sitting too long, Thosar added.
By Dyanne Weiss