Due to differences in modalities , time course , study design and outcomes , it is not possible to define a single ‘ physiological time window ’ for SRC recovery .
Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery , supporting a buffer zone of gradually increasing activity before full contact risk .
Aim or objective The aim of this study is to consoli date studies of physiological measures following sport-related concussion ( SRC ) to determine if a time course of postinjury altered neurobiology can be outlined .
This biological time course was considered with respect to clinical ly relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk .
Cerebral Blood Flow During Treadmill Exercise Is a Marker of Physiological Postconcussion Syndrome in Female Athletes
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 prospect i ve 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
Due to differences in modalities , time course , study design and outcomes , it is not possible to define a single ‘ physiological time window ’ for SRC recovery .
Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery , supporting a buffer zone of gradually increasing activity before full contact risk .
Aim or objective The aim of this study is to consoli date studies of physiological measures following sport-related concussion ( SRC ) to determine if a time course of postinjury altered neurobiology can be outlined .
This biological time course was considered with respect to clinical ly relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk .