Long Sedentary Stretches Can Reduce Kids’ Artery Flexibility


Researchers have found that having children sit still could be the opposite of what kids actually need. If a child sits for long periods of time, changes in blood circulation can occur, even in young children, which can increase the risk of heart disease later in life.

Carina Storrs of CNN points out that the study was made with a very small sample. Nine girls between 7 and 10 were measured for blood flow in their legs prior to and after they spent three hours in beanbag chairs watching movies and playing games on iPads in the lab.

Scientists found that the relaxing sessions were associated with a 33% decrease in the flexibility of the artery of the thigh, similar to what happens to adults when sitting for a long time period. But when the children were asked to sit for three hours and were asked to get up and exercise for 10 minutes every hour, no difference in vessel flexibility was found.

“We didn’t expect quite such a profound effect in children,” partly because children seem like they could be more resilient to sedentary behavior, said Alison McManus, associate professor of pediatric physiology at the University of British Columbia. McManus is lead author of the study, which was published in the journal Experimental Physiology on September 15.

McManus explained that stiffening of the thigh artery could increase the risk of cardiovascular problems by approximately 25% until the vessel regains its flexibility. The concern is that if children are habitually inactive, they could lose the stretchiness in their arteries, and that could put them at risk for heart attack and stroke in adulthood.

Increases in levels of blood sugar, cholesterol and risk of obesity, heart disease and even premature death have all been found in adults who stay glued to their chairs for hours. But this is the first study to look at the effects of sedentary behavior in children.

Children today spend about 60% of their waking time inactive. There is no way of knowing whether this is more or less than in the past since there are no such studies from 10 or 15 years ago.

“This research suggests that children are not that different from adults in terms of fundamental physiology of the body,” Hedge said. “It confirms that sitting compresses blood vessels in young people just as much as it does in adults [and] just as much as it does in elderly.”

If children are asked to move around for 10 minutes every half hour, which is more frequently than in the study (10 minutes every hour), the additional movement could help them remain more alert as well as helping them maintain good bone and muscle health, according to Hedge.

McManus added that this information shows that students should be more active when in school. She says breaking up the day, breaking up the sitting, and getting kids up and moving is a must for kids, reports CBC News Canada.

Evidence shows that uninterrupted sitting hurts the health of adults, but there is also the problem that these risks stay high even if a person exercises regularly but then cozies up in a chair for the rest of the day, writes Gretchen Reynolds of The New York Times.

One recent epidemiology study found that kids globally sit for about 8.5 hours each day. In another study published recently, scientists discovered that after age 8 children’s activity levels drop and continue to fall into adolescence. This finding is most pronounced in girls.

“For perspective,” Dr. McManus said, in adults, a sustained 1 percent decline in vascular function “has been shown to increase cardiovascular disease risk by 13 percent.”

McManus said vigorous exercise is not required to keep children’s arteries in good shape.

Before the experiment, McManus was afraid she would not be able to keep the girls still for three hours. She supposed that they would fidget or wanting to be up and moving around. The opposite was true, and the girls were perfectly content to sit quietly and play games and watch movies.