A new study has found that taking part in structured exercise such as team sports can reduce levels of depression in boys from the age of nine to 11.

Researchers at Washington University in St Louis found children taking part had larger hippocampi volumes – a part of the brain known to play a role in depression, memory and stress response.

Lisa Gorham, lead author of the study, said: “Our findings illuminate the relationships between involvement in sports and depressive symptoms in kids as young as nine.

"We found that involvement in sports is related to greater hippocampal volume in both boys and girls, and is related to reduced depression in boys, but this did not apply to not non-sport activities such as music or art.”

The relationships were particularly strong for children participating in sports that involved structure – such as a school team sports – rather than informal sports.

The findings suggest that there may be added benefits of the team or structured component of sports.

Gorham said the results indicate an association between sports involvement and hippocampal volume in girls, but unlike boys, no additional association with depression. “This might mean that different factors contribute to depression in girls, or that a stronger association to sports involvement might emerge at a later developmental period for girls,” she proposed.

Researchers said the results are correlational, not causational – perhaps participating in sports leads to increased hippocampal volume and decreased depression, or maybe children who are more depressed are less likely to engage in sports and also have smaller hippocampal volume.

“Either scenario could have important implications for understanding childhood depression”, they said.

"The fact these relationships were strongest for team or structured sports suggests there might be something about the combination of exercise and the social support or structure that comes from being on a team that can be useful at preventing or treating depression in young people," said Gorham.

Adult depression has long been associated with shrinkage of the hippocampus.

FOOTNOTE
The report – 'Involvement in Sports, Hippocampal Volume, and Depressive Symptoms in Children' – has been published in the journal 'Biological Psychiatry: Cognitive Neuroscience and Neuroimaging', which is published by Elsevier.