Maintaining a healthy level of fitness in school-age girls may help prevent the onset of depression.

While physical fitness is not the cure-all for depression, research suggests that it can play a role in mitigating the effects, especially in preteen girls. In a study, headed by Camilo Ruggero, assistant professor of psychology from the University of North Texas, researchers found that girls who exercised regularly in sixth grade were less likely to be depressed the next school year.

Ruggero states that no direct reason has been found as to why fitness and weight interact with each other, but he partially associates the link between two to lower weight. There is a body of evidence that suggests that depression is related to a person’s BMI, especially in women. Middle school is also time when physical activity reduces and weight and depression rates increase.

Depression can also lead to reduction in exercise, Ruggero noted. The relationship has not been established to be one way. The study found that boys who experienced depression in sixth grade were more likely to be less physically active in seventh grade.

Other factors may play a role in how fitness effects depression. Evidence suggests that females experience more weight-related depression than males, both as children and adults. The possible factors that go into depression are myriad and the development of depression based on these factors is not easily predicted.

Critics of the study, whose findings are considered preliminary until publication in a peer reviewed journal, point out that causation has yet to be properly determined. Increasing fitness does not necessarily mean that a person’s mental health will improve.

However, the effect of exercise on the mood has been shown to be beneficial. Researchers believe this could be, in part, due to the release of endorphins by the brain during physical activity. Endorphins help diminish the perception of pain and provide a boost to mood that some describe as “euphoric.”

Regardless of whether or not fitness is directly related to mental health, experts agree that it is an important goal to strive towards. This is especially true in children, as early habits often carry through into adulthood just as much as early onset obesity.