Physical exercise: Effects on cognitive function after traumatic brain injury

Persistent cognitive dysfunction (long-term memory, working memory, executive function, attention, visuospatial function, etc.) is present in a substantial proportion of traumatic brain injury patients. Animal studies have demonstrated that aerobic physical exercise can reduce some of the cognitive deficits associated with brain damage (particularly hippocampal-dependent memory), although there are still multiple issues to be resolved with regard to the optimal parameters of this type of intervention. The neural mechanisms involved in the cognitive benefits of exercise are varied and include factors that generally relate to neuroprotection against secondary injury (reduced chronic neuroinflammation, reduced neuron and myelin loss, preserved integrity of brain vasculature, and cerebral blood flow, etc.) and to neurorepair (increased neuroplasticity and neurogenesis). Despite the encouraging results from animal research, there has only been limited success in translating these to the clinical setting. It is expected that further research on animals and humans will contribute to the designing of effective exercise interventions as part of comprehensive patient-rehabilitation strategies.