The Effect of Exercise on Cognition and Preventing Depression in Young People

It is estimated that approximately 30% of child and adolescents manifest subthreshold depression (including other specified depressive disorder and unspecified depressive disorder), which can further develop into major depression with as high as 25%-50% within one year. The cognitive development of adolescents is a critical area of research, given its significant implications for academic performance, mental health, and overall well-being. During adolescence, the brain undergoes substantial structural and functional changes, particularly in regions associated with executive function, memory, and processing speed. These changes provide a unique opportunity to explore interventions that can support and enhance cognitive development. One such promising intervention is physical exercise. Adolescence is characterized by rapid cognitive growth, including improvements in executive functions such as planning, decision-making, and inhibitory control. These cognitive abilities are essential for academic success and social interactions. However, this period also presents risks for cognitive and emotional disturbances, making it vital to identify effective strategies to promote healthy cognitive development. Despite the promising evidence, there is a need for more rigorous research, particularly long-term randomized controlled trials (RCTs), to establish the causal relationship between exercise and cognitive function in adolescents, including those with sub-threshold depression. Most existing studies have focused on short-term interventions or specific cognitive tasks, leaving a gap in our understanding of the sustained effects of exercise over an extended period. Additionally, the transition from supervised to unsupervised exercise and its impact on adherence and cognitive outcomes is underexplored. There is also a need to evaluate the potential of exercise as a preventive strategy against the development of major depressive disorder in this vulnerable population. Additionally, evidence suggests that participants with lower baseline levels of physical activity may experience more significant cognitive improvements from exercise interventions than those with higher baseline activity levels. This highlights the importance of considering baseline physical activity levels when assessing the effectiveness of exercise on cognitive outcomes.

This study will particularly focus on the cognitive domains of attention, memory, and processing speed. These domains are critical for academic success and daily functioning and are often impacted in adolescents with sub-threshold depression. Previous research has shown that these domains are particularly responsive to physical exercise interventions.