Rest has long been the cornerstone of health care professionals' recommendations for optimal recovery from a sports-related concussion. A recently published systematic review suggests that gradually resuming aerobic exercise like cycling and running as early as three days after a concussion is safe and likely beneficial in reducing symptoms as long as exertion does not result in worsening of symptoms. This systematic review examined seven randomized clinical trials (total of 326 adolescents) comparing the effectiveness of exercise programs to relative rest following a sports-related concussion. The intensity of aerobic exercises varied between studies from low to moderate. Although limitations to some of the included studies were found, taken together, these studies show that aerobic exercise is not associated with more adverse events compared to rest and that it is likely beneficial in reducing the intensity of symptoms such as headache and dizziness. In clinical practice, the results of this study suggest that, even in the presence of residual concussion symptoms after a brief initial rest period, clinicians could recommend a gradual progression toward moderate-intensity aerobic exercise, as long as activity does not result in an increase of symptoms.