Association of Hemodynamic and Cerebrovascular Responses to Exercise With Symptom Severity in Adolescents and Young Adults With Concussion

Background and Objectives: Aerobic exercise has become a useful method to assist with post-concussion management. Exercise can exacerbate concussion symptoms even when symptoms are not apparent at rest. Few studies have examined the reasons for symptom exacerbation during exercise following a concussion. We had two primary objectives. 1) To delineate cardiopulmonary and cerebrovascular responses to exercise in adolescents and young adults with a concussion and healthy controls. 2) To determine the association between cerebrovascular responses and symptom burden. Methods: We recruited participants with a recent concussion from a sport concussion clinic between 9/1/2018-2/22/2020. They were included if their concussion occurred Results: We conducted 107 exercise tests (40 concussed, 37 healthy participants initially; 30 concussed at follow-up). Concussed participants were tested initially (mean=17.6±2.2 [SD] years old; 55% female; mean=12.5±4.7 days post-concussion) and again 8 weeks later (mean=73.3±9.5 days post-concussion). Control participants (mean=18.3±2.4 years; 62% female) were tested once. FETCO2 increased throughout the exercise protocol as heart rate increased, reached a plateau, and declined at higher exercise intensities. CO2 explained >25% of the variation in resting CBF (R2>0.25; p Discussion: The arterial CO2 response and symptom exacerbation relationship during post-concussion aerobic exercise may be mediated by increased sensitivity of cerebral vasculature to exercise-related increase in CO2.