How physical activity can protect against depression

Adolescence is a critical time for the development of mental health problems, say VU researchers.

Professor Alexandra Parker (Physical Activity and Mental Health) and Michaela Pascoe (Postdoctoral Research Fellow in Exercise and Mental Health) explain why it's so important to try to prevent depression in young people, and how exercise can help.

The consequences of depression in adolescence are serious and can be lifelong. At least one‐quarter of young people will experience an episode of depression before 19 years of age. And by Year 9, students who have experienced a mental disorder are on average two years behind in academic achievement compared to those without a mental disorder.

Many young people don’t recover from depression, despite treatment with the best available evidence‐based treatment approaches.

Longterm consequences include:

• an increased risk of depression late in life
• poor social functioning and academic achievement
• reduced employment security
• greater risk of suicide and self‐harm.

An increasing body of evidence indicates physical activity and exercise are effective for improving mood. Studies show that exercise and physical activity are effective as a depression-prevention approach for young people.

How much physical activity do young people need to do?

The Australian guidelines state young people should engage in 60 minutes of physical activity a day. The majority of young people don’t reach this target.

In fact, disengagement from regular exercise, physical activity and sporting clubs steadily increases during adolescence. This coincides with the average age of onset of depression.

Physical activity is an important part of the Australian Curriculum. The Australian national policy requires government schools to provide at least two hours of physical activity per week during primary education and junior secondary education. Physical education is not required as part of the senior secondary curriculum. Even during primary education and junior secondary education, the mandated 120 minutes a week doesn’t meet Australian guidelines.

Schools are a key site for the promotion of healthy behaviours. Many long-term health-related behaviours and patterns – both positive and negative – are established during the developmental phase of adolescence and early adulthood.

How do we get them to do more?

Physical activity is an acceptable, non-stigmatising approach to promoting better mental health in young people. To meet the specific needs of young people, a physical activity program should facilitate self-reliance, motivation, and mental health and wellbeing literacy.

Motivation to engage in physical activity can be increased by offering choice of activities, increasing skills and ability to engage in physical activity, and opportunities for social connection.

Schools are best placed to ensure that young people meet the Australian guidelines for physical activity each day. Most school-based intervention studies of physical activity have used supervised programs of moderate to vigorous physical activity. These consist of 30 to 45 minute sessions, three to five days per week. The physical activity should include a variety of activities, be age-appropriate and enjoyable.

Some researchers suggest schools could also promote physical activity outside physical education classes by ensuring at least 20 minutes of recess per day.

Finally, physical educators can be key drivers of physical and health literacy and behaviour change. They can do this, for example, through school-based activities and by providing information about the benefits of physical activity via newsletters and notices sent home.