Scientists are already aware that physical activity will help lower the risk of adult depression. A new study suggests that young active adults, relative to their sedentary counterparts, are less likely to experience depression symptoms by age 18.
“Our findings show that young people who are inactive during adolescence for large proportions of the day face a higher risk of depression by age 18,” reports Aaron Kandola, a doctoral student at University College London, United Kingdom.
Recently, Kandola and colleagues conducted research into correlations between levels of physical exercise and risk of depression among adolescents. Our results are published in the journal The Lancet Psychiatry.
The findings of the team reinforce current ideas that physical activity is not only good for the body but also for the mind.
In addition, the study shows that intense activity is not required to reap the benefits — light exercise may be appropriate.
“Worryingly, the amount of time spent inactively by young people has been steadily increasing for years, but there has been a startling lack of high-quality research on how this could impact mental health. It also appears that the number of young people with depression is that and our study suggests that these two patterns may be related,” says Kandola.
Light activity tied to lower depression
The team analyzed data from 4,257 participants who were involved in the cohort study of the 90s Children of the University of Bristol. We looked mainly at the information gained while the participants were aged 12, 14 and 16.
The information included data about physical activity collected by accelerometers that the adolescents had decided to wear for a span of 3 days for at least 10 hours.
The researchers were able to find out, thanks to the accelerometers, whether the children had participated in light activity, moderate-to-vigorous activity or had largely led sedentary lives.
The investigators clarify in this context that light activity could include walking, whereas moderate-to-vigorous activity may apply to running or riding a bike.
The researchers also took into account reports of symptoms of depression — such as low mood and lack of enjoyment in previously enjoyed activities— by means of detailed questionnaires.
By looking at these results, the team found that overall the levels of physical activity among adolescents decreased between the ages of 12 and 16, during which time the participants became more sedentary.
The researchers also found that there was an improvement in the depression scores of teenagers by the time they turned 18 for each extra 60 minutes of inactivity per day at age 12, 14 and 16. This rise was respectively 11.1 percent, 8.0 percent, and 10.5 percent.
Additionally, the adolescents had lower depression levels by age 18 for any additional hour spent a day engaging in light physical exercise at age 12, 14, and 16. The cuts were respectively 9.6 percent, 7.8 percent, and 11.1 percent.
“We found that it’s not just more vigorous types of activity that are good for our mental health— any degree of physical activity that may reduce the time we spend sitting down is likely to be beneficial,” Kandola says.
“We should be inspiring people of all ages to walk more and sit less, because this is beneficial for our physical and mental health,” he says.
‘Easy to fit into daily routines’
The team also found several correlations in late adolescence between taking moderate-to-vigorous exercise and lower scores of depression. They warn however that they did not have enough data to determine this association’s power.
Ultimately, because the study was retrospective, the authors understand that they can not assert the presence of a causal relationship between physical activity rates and the frequency of symptoms of depression.
Nonetheless, they note that the correlation between light physical activity and apparently better mental health remained in place despite having accounted for confounding factors— including the socioeconomic status of the participants and the mental health history of their parents.
“Some programs encourage exercise among young people, but our findings suggest that more attention should be paid to light activity as well,” states senior author of the study, Joseph Hayes, Ph.D.
“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.”
– Joseph Hayes, Ph.D.
