Sedentary behavior linked to teenage dejection

LONDON－Sitting still for too long on a daily basis is linked to an increased risk of depressive symptoms in adolescents, states a recent report published by the University College London.

The research team used data from 4,257 adolescents, who have been participating in longitudinal research from birth as part of the University of Bristol's Children of the 90s cohort study. The children wore accelerometers to track their movement for at least 10 hours over at least three days, at ages 12, 14 and 16.

Depressive symptoms, such as low mood, loss of pleasure and poor concentration, were measured with a clinical questionnaire.

Between the ages of 12 and 16, total physical activity declined across the cohort, which was mainly due to a decrease in light activity and an increase in sedentary behavior.

The researchers found that every additional 60 minutes of sedentary behavior per day at ages 12, 14 and 16 was associated with an increase in depression score of 11.1 percent, 8 percent or 10.5 percent, respectively, by age 18.

The team also found that those with consistently high amounts of time spent sedentary at all three ages had 28.2 percent higher depression scores by age 18.

"Our findings show that young people who are inactive for large proportions of the day throughout adolescence face a greater risk of depression by age 18," said the study's lead author, PhD student Aaron Kandola at the UCL.

"We found that it's not just more intense forms of activity that are good for our mental health, but any degree of physical activity that can reduce the time we spend sitting down is likely to be beneficial," Kandola said.