Subsymptom threshold exercise training for patients with exercise intolerance after mild traumatic brain injury – a pilot study

Objective: Evaluate the applicability of the Buffalo Concussion Treadmill Test (BCTT) and subsymptom threshold exercise training for nonathletes with mild TBI and refractory post-concussion symptoms. Explore the influence of subsymptom threshold exercise on post-concussion symptoms and health related quality of life (HRQL). Methods: Pilot study. 29 patients (16 female), median age 35 years (23-54) with exercise intolerance after mild TBI was included. Outcomes: BCTT, physical activity (activity index), Rivermead Post Concussion Symptoms Questionnaire (RPQ) and Quality of Life after Brain Injury (QOLIBRI). Subsymptom treshold exercise was performed for 13 weeks (IQR 10-15). Results: No adverse reactions on the BCTT and subsymptom threshold exercise training were reported. Twenty-three patients were retested. At retest we registered a significant improvement on the BCTT parameters (test duration p<0.001, HF p=0.001, perceived exertion on Borg RPE scale p=0.01) and on the activity index (0.002). There was a significant improvement in post-concussion symptoms (RPQ) (p=0.01) and HRQL (QOLIBRI) (p<0.001). Conclusion: The BCTT and subsymptom threshold exercise training was safe and applicable in this pilot study. Subsymptom threshold exercise training may improve exercise intolerance, level of physical activity, post-concussion symptoms and HRQL.