Teen girls spend 19 hours a day ‘sitting or lying down’

After finding that teenage girls spend as much as 19 hours a day sitting or lying down, University of Limerick researchers are now studying whether this inactivity can lead to heart problems.

The UL study has received funding from the Irish Heart Foundation.

Professor Alan Donnelly, of the college’s Centre for Physical Activity and Health Research, will lead the study. He and his team found that teen girls spend an average of 19 hours a day either sitting or lying down.

“There is no doubt performing moderate or vigorous physical activity is good for the long-term health of adolescents,” Prof Donnelly said.

“However, we believe 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.”

Prof Donnelly said 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.

He said: “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.

“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 are 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.”

This research, he said, will take a new and very different approach to changing adolescent health risk; instead of a focus on sport and high intensity activity, it will examine the effects of sitting and the potential effects of light-intensity physical activity.

Prof Donnelly said: “Sitting time is surprisingly 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.

“Our research centre in Limerick has developed analysis techniques for these devices that enable us to record and quantify sitting time, standing time and physical activity intensity.

“We have previously collected and published data showing that adolescent girls sit for a large part of their waking day, and this study will extend that work by tracking 100 male and females from late adolescence through to early adulthood, to observe whether sitting and the associated risk from sitting are modified when adolescents leave school and go to college or into the workplace.”