The role of sub-symptom threshold aerobic exercise for persistent concussion symptoms in patients with post-concussion syndrome: A systematic review.

In recent years, there has been a shift away from rest until total symptom resolution after concussion, due to the potential adverse consequences of inactivity. Aerobic exercise has been increasingly investigated for the treatment of postconcussion syndrome, whereby symptoms persist beyond 4 wks. The aim of this review was to systematically review the literature on subsymptom threshold aerobic exercise as a treatment for postconcussion syndrome. We conducted systematic literature searches in databases: MEDLINE (Ovid), CINAHL, PubMed, and Embase. After thorough review, 12 articles met the eligibility criteria and were included in the systematic review. The quality of selected studies was low to moderate. Subsymptom threshold aerobic exercise was associated with improvement in symptoms in patients with postconcussion syndrome for all included studies. The most commonly used protocols incorporated 20 mins of exercise at 80% of the heart rate that provoked symptoms, 5-6 days per week, with no adverse events documented. However, there was considerable variation in exercise protocols, and many studies incorporated subsymptom threshold aerobic exercise as part of a broader rehabilitation plan. Evidence supports subsymptom threshold aerobic exercise as a promising treatment for postconcussion syndrome. Further studies are required to delineate the optimal intensity, duration, and frequency of exercise for postconcussion syndrome in a variety of populations.