Teenage girls spend almost 20 hours a day either sitting or lying down

University of Limerick study shows impact of inactivity

Teenage girls spend almost 20 hours a day either sitting or lying down, which may cause a risk to their cardiovascular health, researchers have found.

A University of Limerick study which seeks to understand the impact of long periods of inactivity among adolescents on their cardiovascular health has received funding from the Irish Heart Foundation.

Led by Prof Alan Donnelly, of the Centre for Physical Activity and Health Research, UL, the study is entitled Sitting around all day doing nothing? The effects of sitting, standing and light activity on adiposity and cardiovascular disease risk in adolescents.

In an associated study, Prof Donnelly and his team found that teenage girls spend an average of 19 hours a day either sitting or lying down.


Prof Donnelly explained: “There is no doubt that performing moderate or vigorous physical activity is good for the long-term health of adolescents. However, we believe that long periods of sitting might be a separate risk factor in this group. Replacing some of this sitting time with light activity might be an effective means of improving health risk and reducing the risk of obesity in these adolescents.”

The proportion of adolescents who are overweight and obese is rising in many developed nations, and Ireland is no exception; one in five Irish adolescents is overweight or obese.

This change in body composition is likely to increase the risk of these adolescents developing heart and arterial disease as they age, according to Prof Donnelly.

“There is evidence that children and adolescents have become more inactive in recent times, as heavy physical chores and active transport have decreased, and seated activities like watching TV, social networking and gaming have increased.

“To date, the response to this has been to encourage adolescents to engage in sport or other high-intensity activities, but many adolescents find this difficult to sustain,” he added.

According to Prof Donnelly, sitting time is hard to measure accurately, but recent technological developments have allowed the direct examination of sitting through a leg-worn device that accurately records sitting behaviour over seven days or more.