June 20, 2014

How Exercise Heals The Brain

While the myriad benefits of physical activity have long been acclaimed when it comes to the general population, less attention has been given to the power of exercise to transform the lives of people with atypical brains. The term “autism spectrum disorders,” or ASD, describes a range of pervasive developmental disorders, including Asperger’s syndrome and PDD-NOS, that differ in severity but generally share deficits in social functioning and communication. In addition, individuals on the autism spectrum tend to exhibit restricted, repetitive, and stereotyped patterns of behavior or interests.

The Good News about ASD and Exercise

While people with autism spectrum disorders tend to be less physically active than their neurotypical peers1 (even when they are sufficiently capable of performing the motor tasks involved), recent research has uncovered some remarkable benefits that can be attained by ASD individuals participating in regular exercise.

A 2010 review by Lang et al. that examined physical activity interventions for ASD participants noted significant decreases in stereotypy, aggression, and off-task behavior among the 64 participants.2 In addition, participants showed improvements in on-task behavior, academic engagement, and appropriate motor behavior following vigorous exercise. A similar review by Sowa & Meulenbroek also found improvements in social functioning when participants were provided with an individualized exercise program. 3 The above findings, combined with what we know about the ability of the brain to transform itself in response to physical exercise, are not only great news for individuals on the autism spectrum and their families but for scientists and caregivers as well: They can teach us more about how the autistic brain functions when considered alongside some recent anatomical and functional discoveries.

How Exercise Heals the Brain

Some studies have found that, in people with ASD, the amygdala and hippocampus are reduced in size compared to the total brain volume, and this likely reflects the underdevelopment of the neural connections of limbic structures with other parts of the brain, particularly the cortex. 4 Exercise, on the other hand, has been associated with increases in hippocampal tissue and encourages the growth of new brain cells by boosting BDNF (brain-derived neurotrophic factor) in the prefrontal cortex. 5 While we won’t know with any certainty until further studies are conducted, it may be possible that the growth of new cells in the hippocampus and the modulation of existing connections in the prefrontal cortex—an area heavily involved in attention, planning, impulse control, and even empathy—is responsible for the improvements in function exhibited by ASD individuals who exercise.

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One specific area whose structure and function seems to be altered in autism spectrum disorders is the anterior cingulate gyrus, which helps the brain shift its attention and adapt to change when needed.6 Given the restricted, repetitive behaviors of many autistic individuals, as well as a general resistance toward change or unexpected circumstances, the involvement of this area is indeed likely. Changes have also been observed in this area in response to physical exercise, which may help confirm theories of involvement in ASD.5

In addition to the fascinating functional data that can be obtained, interventions and perhaps even social skills training centered around a regular exercise routine can have a profound positive impact on the lives of those affected by autism spectrum disorders. No such program currently exists on a large scale, but as we uncover ever more fascinating ways in which physical activity can transform the human brain, medical practitioners and therapists alike will be sure to increase the emphasis they place on exercise as a critical component of their patients’ treatment.

Citations

Magnusson et al. (2012). Beneficial effects of clinical exercise rehabilitation for children and adolescents with autism spectrum disorder. Journal of Exercise Physiology Online 15(2).
Lang et al. (2010). Physical exercise and individuals with autism spectrum disorders: A systematic review. Research in Autism Spectrum Disorders 4(4):565-576.
Sowa & Meulenbroek. (2012). Effects of physical exercise on autism spectrum disorders: A meta-analysis. Research in Autism Spectrum Disorders 6(1):46-57.
Aylward et al. (1999). MRI volumes of amygdala and hippocampus in non–mentally retarded autistic adolescents and adults. Neurology 53(9):2145.
Amen, D. (2010). Change Your Brain, Change Your Body. Three Rivers Press. New York: New York.
Haznedar et al. (1997). Anterior cingulate gyrus volume and glucose metabolism in autistic disorder. The American Journal of Psychiatry 154(8): 1047-1050.