Physical Activity for Cognitive and Mental Health in Youth: A Systematic Review of Mechanisms

Abstract

CONTEXT: Physical activity can improve cognitive and mental health, but the underlying mechanisms have not been established. OBJECTIVE:To present a conceptual model explaining the mechanisms for the effect of physical activity on cognitive and mental health in young people and to conduct a systematic review of the evidence.DATA SOURCES: Six electronic databases (PubMed, PsycINFO, SCOPUS, Ovid Medline, SportDiscus, and Embase) were used.STUDY SELECTION: School-, home-, or community-based physical activity intervention or laboratory-based exercise interventions were assessed. Studies were eligible if they reported statistical analyses of changes in the following: (1) cognition or mental health; and (2) neurobiological, psychosocial, and behavioral mechanisms.DATA EXTRACTION: Data relating to methods, assessment period, participant characteristics, intervention type, setting, and facilitator/delivery were extracted. RESULTS:Twenty-five articles reporting results from 22 studies were included. Mechanisms studied were neurobiological (6 studies), psychosocial (18 studies), and behavioral (2 studies). Significant changes in at least 1 potential neurobiological mechanism were reported in 5 studies, and significant effects for at least 1 cognitive outcome were also found in 5 studies. One of 2 studies reported a significant effect for self-regulation, but neither study reported a significant impact on mental health. LIMITATIONS:Small number of studies and high levels of study heterogeneity. CONCLUSIONS:The strongest evidence was found for improvements in physical self-perceptions, which accompanied enhanced self-esteem in the majority of studies measuring these outcomes. Few studies examined neurobiological and behavioral mechanisms, and we were unable to draw conclusions regarding their role in enhancing cognitive and mental health.

The Relation of Physical Activity, Sedentary Behaviors, and Academic Achievement Is Mediated by Fitness and Bedtime

“…PA and aerobic fitness have been suggested to enhance cognitive functions by inducing functional and structural changes in subcortical structures such as the hippocampus and the basal ganglia, 31 through cortical structures such as prefrontal cortex, 32 by increasing levels of brainderived neurotrophic factor and by enhancing cerebrovascular function. 33 Beside the beneficial effects on cognition, PA may improve academic engagement, 34 self-esteem, 31,35 and school contentment, 36 all of which predict better AA. Furthermore, motor function may be an important driver in the effects of PA on the cognitive prerequisites of learning.…”

Physical activity and mental health: commentary on Suetani et al. 2016: common mental disorders and recent physical activity status: findings from a National Community Survey

“…However, despite over 60 years of PA epidemiology, our understanding of the associations between PA and mental health is still very limited; the evidence to date is mixed, and hampered by methodological weaknesses [3][4][5][6]. There is some evidence from recent systematic reviews that PA can be effective in reducing depressive symptoms, and positive symptoms of schizophrenia, in adults with mental illness [5], but associations between PA and other mental health problems, and whether PA can prevent mental health problems in the general population, are unclear [5,6].…”

“…There is some evidence from recent systematic reviews that PA can be effective in reducing depressive symptoms, and positive symptoms of schizophrenia, in adults with mental illness [5], but associations between PA and other mental health problems, and whether PA can prevent mental health problems in the general population, are unclear [5,6]. Hypothesised mechanisms for associations between PA and mental health include biological (e.g., physiological stress responses and inflammation), psychosocial (e.g., social support), and psychological (e.g., self-esteem) effects [3], but few studies have explored underlying mechanisms in detail [3].…”

“…However, as acknowledged by the authors, numerous methodological limitations preclude any conclusions at this stage. Arguably the most notable methodological weaknesses-typical of most studies of PA and mental health [3][4][5][6]-are the reliance on self-report (and dichotomised) PA data, and the crosssectional study design, as discussed below.…”

“…They can also provide important information on type and context of PA (e.g., team sports vs. individual sports, occupational vs. recreational activity, etc. ), which is likely of particular importance in mental health research given the various potential mechanisms involved [3]. However, self-report measures of PA are prone to bias (e.g., recall, social desirability), have relatively low test-retest reliability, are unable to accurately capture information on duration, intensity and frequency of PA [8], and might, therefore, conceal or exaggerate true associations.…”