Patients who do not fully recover from a concussion in 7–14 days may require an impairment-based rehabilitation program. Recent evidence indicates improved outcomes with active rehabilitation compared to passive physical and cognitive rest. In patients with persistent symptoms (greater than 4 weeks) following concussion, how does aerobic exercise affect postconcussion symptoms? There is moderate and sufficient SORT Level B evidence to support the inclusion of subsymptom threshold (SST) exercise in the multimodal treatment plan for patients suffering from persistent symptoms after concussion. All five included studies reported moderate to very large effects ranging from d= 0.72 to d= 10.64 in reducing symptoms after the implementation of SST aerobic exercise. Additionally, two studies also identified moderate and very large effects (d= 0.77, d= 2.56) favoring aerobic exercise over stretching interventions. These results indicate that this treatment has potential clinical utility and is a viable option to reduce symptoms in patients with postconcussion syndrome and persistent symptoms following concussion.