Effects of Sub–Symptom Threshold Aerobic Exercise on Persistent Postconcussion Symptom Burden and Exercise Intolerance: A Randomized Controlled Trial

Abstract Importance Persistent postconcussion symptoms (PCS) following mild traumatic brain injury (mTBI) are common and are often associated with exercise intolerance. The effects of aerobic exercise on PCS in adolescent athletes have been promising. However, randomized controlled trials targeting persistent PCS in the adult population are needed. Objective The objective of this study was to evaluate the effects of sub–symptom threshold aerobic exercise (SSTAE) on symptom burden and exercise intolerance in adults with persistent PCS. Design This was a randomized (1:1) controlled single-blind, parallel-group trial with follow-up at 12 weeks and 6 months. Setting The setting was a TBI outpatient clinic at Oslo University Hospital, Norway. Participants The participants were 81 adults who were 18 to 59 years old and had PCS and exercise intolerance 3 to 24 months after mTBI. Interventions The interventions were treatment-as-usual plus SSTAE versus treatment-as-usual including only general exercise information and advice. Main Outcomes and Measures The primary outcome was symptom burden, measured with the Rivermead Post-Concussion Symptoms Questionnaire. The secondary outcome was exercise intolerance, measured as the symptom threshold and minutes to stop on the Buffalo Concussion Treadmill Test. Tertiary outcomes were measurements of health-related quality of life, depression, anxiety, fatigue, and level of physical activity. Results No between-group differences were observed in the Rivermead Post-Concussion Symptoms Questionnaire at 12 weeks or 6 months. SSTAE significantly improved the Buffalo Concussion Treadmill Test symptom threshold at 12 weeks, with effects sustained at 6 months. Additionally, the SSTAE group was superior to the control group in minutes to stop at 12 weeks but not at 6 months. No adverse events occurred. No statistically significant treatment effects were observed for the tertiary outcomes. Conclusions The added benefit of SSTAE to treatment-as-usual did not lead to greater reduction in symptom burden compared to the control group. However, SSTAE significantly improved exercise intolerance and was safe and well tolerated. Both groups improved over time in symptom burden, health-related quality of life, depression, anxiety, and fatigue. Relevance Symptom restricted aerobic exercise intervention, provided by physical therapist, improves exercise intolerance in patients with persistent symptoms after mTBI. Relevance Symptom restricted aerobic exercise intervention, provided by physical therapist, improves exercise intolerance in patients with persistent postconcussion symptoms after mTBI.