A study by researchers at University College London looked at the activity levels of 4,257 12- to 16-year-olds and has found that children who spend lots of time sitting still are more likely to develop depression by the age of 18.
According to the researchers those who did an additional hour of light activity each day, such as walking or chores, had fewer depressive symptoms when they reached adulthood.
The study suggests people of all ages should be encouraged to move more.
The participants, from the University of Bristol's Children of the 90s cohort study, wore accelerometers for at least 10 hours on at least three consecutive days (except when they were washing or doing water sports) at the ages of 12, 14 and 16. It showed whether they were sitting still, engaging in light activity - such as walking or engaging in moderate to vigorous activity - such as running or cycling. The participants had to fill out a questionnaire that measured depressive symptoms such as low mood, loss of pleasure and poor concentration.
Between the ages of 12 and 16, physical activity declined, while sedentary behaviour increased, the study says.
Researchers found the average time per day spent on:
- sitting still rose from about seven hours to eight and a half
- light activity decreased from about five and a half hours to four
- moderate to vigorous activity "remained stable"
They found for every additional hour a day spent sitting still at the ages of 12, 14 and 16, the participants' depression score rose by 11.1%, 8% and 10.7%, respectively.
