Safety and Efficacy of Sub-Maximal Aerobic Exercise during the Sub-Acute Phase of Recovery Following Sport-Related Concussion

Previous research suggests that strict rest following a concussion may prolong symptom presentation, but rest is still one of the most common treatments. Aerobic exercise has effectively reduced symptom burden and exercise intolerance in patients experiencing persistent symptoms longer than 30 days; however, treatment outcomes with sub-acutely concussed patients have not been described. PURPOSE: The purpose of this study was to (1) demonstrate the systemic dysfunction following a sport-related concussion; and (2) examine the safety and efficacy of a 20-minute, low- or moderate-intensity (40% or 60% of HRMAX) controlled treadmill aerobic exercise as a therapeutic modality to improve cardioautonomic, neurological, and psychological function. METHODS: Thirty participants [16.0 ± 1.3 years; 19 sport-related concussed (SRC) and 11 healthy, non-concussed (NC)] were assigned to one of three treatments [1) 40% Age-Predicted HRMAX; 2) 60% Age-Predicted HRMAX; or 3) seated rest using a randomized double block design. SRC participants were evaluated between Day 3-7 of their injury and performed the treatment on the same day. Serial monitoring was performed at rest, during the acute bout of exercise, and recovery. The SRC participants were tracked until clinical recovery. RESULTS: Demographic variables were no different across groups. Autonomic function was not different across groups. Diastolic blood pressure and mean arterial pressure were significantly higher in the SRC participants. A greater percentage of exercising SRC participants improved on measures of ocular motor and vestibular function and symptom reporting compared to the resting SRC participants. 100% of the 40% HRMAX SRC participants and 86% of the 60% HRMAX SRC participants completed the session. Student-athletes who were prescribed exercise following their initial visit reported approximately five days faster than those who were prescribed rest in a previous clinical dataset. CONCLUSIONS: The 40% treatment reported 100% completion rates while both the 40% and 60% groups improved symptoms. Future studies should seek to examine middle school, collegiate, and professional athletes as well as non-athlete populations.