Effects of a School-Based Exercise Intervention Program on Stress and Executive Functioning in Adolescents with Autism Spectrum Disorder or Other Special Education Needs

Background:  Extensive research has shown that physical exercise produces positive impacts on physical and psychological health indicators across numerous populations. With regards to psychological health, evidence suggests reduced stress and improved executive functioning as a result of exercise. As a clinical intervention, exercise has a number of advantages, including feasibility of implementation by staff at various levels of training, or by patients themselves, and completion at low cost to both the individual and society. Thus, exercise intervention has great potential to be a potent and pivotal intervention for improving the health and well-being of individuals with psychiatric disorders. Autism Spectrum Disorder (ASD) is associated with significantly elevated symptoms and rates of anxiety, as well as difficulties with executive functions including inhibitory control and attention switching. However, very little research has been conducted on exercise as an intervention for individuals with ASD to date.

Objectives:  To investigate the impacts of a school-based exercise intervention on stress and executive functioning in adolescents with ASD or other Special Education Needs (SEN).

Methods:  A Within-Subjects Experimental Design was utilized, with each participant partaking in 1) one week of Exercise Intervention (20-minutes of aerobic exercise per day), and 2) one week of Education As Usual (EAU). Intervention condition order was randomized across classroom (n=2), with ASD and SEN participants distributed across classrooms. The exercise intervention was implemented by regular school staff, without specialist equipment or resources. Participants were adolescents with ASD (n=24; 1f, 23m) or other SEN (n=29; 15f, 14m) with intellectual abilities within the normal to low range, matched on Chronological Age (p=0.24), Verbal Abilities (British Ability Scales Word Definition and Verbal Similarities; p=0.13), and Nonverbal Abilities (British Ability Scales Matrices; p=0.80). The Stress Survey Scale for Individuals with Autism or Other Pervasive Developmental Disorders (SSS; Groden et al., 2001), and computer-based tasks indexing the executive functions of Inhibitory Control and Attention Switching (Burns, Riggs, & Beck, 2012), were each administered during both the Exercise Intervention and EAU conditions. Experimentally blinded research assistants conducted these tasks within 90-minutes of completion of the 4^th (Thursday) and 5^th (Friday) sessions of each week.

Results:  We observed significant reductions in self-reported stress with Exercise relative to EAU (SSS; Exercise M=97.04, SD=23.88; EAU M=107.71, SD=24.38, F(1,52) = 19.920; p < 0.001, np2 = .281). We also observed significant improvements in both of the Executive Function tasks. For the Inhibition Task, Exercise Intervention significantly reduced Congruent/Incongruent trial difference relative to EAU, reflecting improved inhibitory control (Accuracy: F(1,51) = 12.236, p < 0.001, np2 = .193). For the Attention Switching Task, Exercise Intervention reduced Switch/Non-Switch trial difference relative to EAU, reflecting improved attention switching ability (Accuracy: F(1,50)= 15.336, p < 0.001, np2 = .246). These effects did not interact with Group (ASD, SEN), and each effect maintained statistical significance when analyzed separately for the ASD and SEN groups.

Conclusions:  The current findings provide evidence for the effectiveness of a school-based aerobic exercise intervention program for reducing stress and enhancing executive functioning in adolescents with ASD.