Children who sit for hours a day are more likely to get depression at the age of 18, a study has warned.
Researchers tracked activity levels of 4,200 youngsters aged between 12 and 16 using activity trackers. Then they quizzed them on their mental health at adolescence.
For every 60 minutes a child spent on the sofa per day, their depressive symptoms at 18 rose by 10 per cent.
Those with consistently high amounts of time spent sedentary had 28.2 per cent higher depression scores by age 18.
Light activity appeared to offset the effects – even more reason to encourage children to do the chores.
For every 60 minutes a child aged between 12 and 16 spent on the sofa per day, their depressive symptoms at 18 rose by 10 per cent, a study found
Study lead author Aaron Kandola, a University College London (UCL) PhD student, said: ‘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.
‘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.
‘We should be encouraging people of all ages to move more, and to sit less, as it’s good for both our physical and mental health.’
The research team used data from more than 4,257 adolescents and published their findings in The Lancet Psychiatry journal.
The children have been participating in research from birth as part of the University of Bristol’s Children of the 90s study.
Accelerometers were used to track their movement for at least 10 hours over at least three days, at ages 12, 14 and 16.
The accelerometers reported whether the child was engaging in light activity, which could include walking or hobbies such as playing an instrument, engaging in moderate-to-physical activity – such as running or cycling, or if they were sedentary.
The use of accelerometers provided more reliable data than previous studies which have relied on people self-reporting their activity.
Depression was assessed with a questionnaire rather than using a clinical diagnosis. Participants were asked about symptoms, such as low mood, loss of pleasure and poor concentration.
A score was calculated on a scale of *.
Between the ages of 12 and 16, total physical activity declined across the group. Light activity dropped from an average of five hours, 26 minutes to four hours, five minutes.
There was an increase in sedentary behaviour from an average of seven hours and 10 minutes to eight hours and 43 minutes.
The researchers found that every additional 60 minutes of sedentary behaviour per day at age 12, 14 and 16 was linked to an increase in depression score of 11.1 per cent, eight per cent or 10.5 per cent, respectively, by age 18.
Those with consistently high amounts of time spent sedentary at all three ages had 28.2 per cent higher depression scores by age 18.
The findings showed that an additional 60 minutes of light activity – such as walking or doing chores – daily lowered depressive symptoms by 10 per cent at age 18.
For age 12, 14 and 16, it reduced depression scores at age 18 by 9.6 per cent, 7.8 per cent and 11.1 per cent, respectively.
The team accounted for potentially confounding factors such as socio-economic status, parental history of mental health, and length of time wearing the accelerometer.
The researchers found some evidence that moderate-to-vigorous activity at earlier ages reduced depressive symptoms.
However, they cautioned that their data was weaker due to low levels of activity of such intensity in the group, averaging around 20 minutes per day.
They said their findings do not clarify whether moderate-to-vigorous activity is any less beneficial than light activity.
Mr Kandola said: ‘Worryingly, the amount of time that young people spend inactive has been steadily rising for years, but there has been a surprising lack of high quality research into how this could affect mental health.
‘The number of young people with depression also appears to be growing and our study suggests that these two trends may be linked.’
Study senior author Dr Joseph Hayes, of UCL and Camden and Islington NHS Foundation Trust, added: ‘A lot of initiatives promote exercise in young people, but our findings suggest that light activity should be given more attention as well.
‘Light activity could be particularly useful because it doesn’t require much effort and it’s easy to fit into the daily routines of most young people.
‘Schools could integrate light activity into their pupils’ days, such as with standing or active lessons.
‘Small changes to our environments could make it easier for all of us to be a little bit less sedentary.’