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Cerebral Blood Flow During Treadmill Exercise Is a Marker of Physiological Postconcussion Syndrome in Female Athletes

Clausen, Mary MS; Pendergast, David R. EdD; Willer, Barry PhD; Leddy, John MD

Section Editor(s): Caplan, Bruce PhD, ABPP; Bogner, Jennifer PhD, ABPP; Brenner, Lisa PhD, ABPP

Journal of Head Trauma Rehabilitation: May/June 2016 - Volume 31 - Issue 3 - p 215–224
doi: 10.1097/HTR.0000000000000145
Original Articles

Objective: Some patients with postconcussion syndrome (PCS) have reduced exercise capacity that may reflect altered central cardiorespiratory control. The purpose of this study was to evaluate control of cerebral blood flow (CBF) during exercise in females with PCS.

Setting: University Concussion Clinic.

Participants: Nine female Division 1 collegiate team athletes with PCS (23 ± 6 years) and a reference group of 13 healthy female recreational aerobic athletes (21 ± 3 years).

Design: A prospective experimental study. All PCS athletes were compared with the reference group at the beginning of the study. Six of the PCS athletes were subsequently measured before and after a subsymptom threshold aerobic exercise treatment program.

Main Measures: Exercise treadmill test during which blood pressure (BP), minute ventilation (

E), end-tidal CO2 (PETCO2), and CBF velocity (CBFV, by transcranial Doppler) were measured.

Results: Participants with PCS had significantly lower

E (by 18%) and greater PETCO2 (5%) and CBFV (14%) versus the reference group at similar workloads in association with appearance of symptoms and premature exercise cessation. Subthreshold exercise normalized

E, PETCO2, CBFV and exercise tolerance. Before treatment, PCS had low CO2 sensitivity that blunted their exercise ventilation. CO2 sensitivity and ventilation improved after exercise treatment.

Conclusion: Some PCS patients have exercise intolerance due to abnormal CBF regulation that may be the result of concussion-induced altered sensitivity to CO2. Return of normal CBF control and exercise tolerance may be physiological markers of recovery from concussion.

Supplemental Digital Content is Available in the Text.

Department of Physiology, Center for Research and Education in Special Environments, State University of New York, Buffalo (Ms Clausen and Dr Pendergast); SUNY Buffalo, Orthopaedics, University Sports Medicine, Buffalo, New York (Dr Leddy); and Department of Psychiatry, SUNY Buffalo (Dr Willer).

Corresponding Author: John Leddy, MD, SUNY Buffalo, Orthopaedics, University Sports Medicine, 160 Farber Hall, Buffalo, NY 14214 (

Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal's Web site (

The authors declare no conflicts of interest.

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