ADOLESCENTS who sit for much of the day have a greater risk of depression by the time they reach adulthood, a study has found.
Growing numbers of young people with depression and increased time spent sedentary could be two linked trends, researchers at University College London (UCL) believe.
They found that those who did an additional hour of light activity each day, such as walking or chores, saw a reduction in depressive symptoms by age 18.
They analysed data on 4,257 adolescents. The participants wore devices at ages 12, 14 and 16 which showed whether they were sedentary, engaging in light activity such as playing an instrument or moderate to physical activity such as running. They also answered a questionnaire which measured depressive symptoms.
Between ages 12 and 16, physical activity declined while sedentary behaviour increased. Time spent on light activity decreased from an average of five-and-a-half hours to just over four hours. Sedentary behaviour rose from an average of just over seven hours to eight hours 45 minutes.
For every additional hour of sedentary behaviour per day at age 12, 14 and 16, the participants' depression score calculated from the questionnaire rose by 11.1 per cent, 8 per cent or 10.7 per cent, respectively, by age 18.
Those who spent consistently high amounts of time sedentary at all three ages had 28.2 per cent higher depression scores by age 18 than those who were rarely sedentary. Depression scores were 19.6 per cent lower in participants with consistently high levels of light activity.
"We should be encouraging people of all ages to move more, and to sit less," said Aaron Kandola, lead author of the study, published in Lancet Psychiatry.
