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Affiliation
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Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS. |
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Abstract
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INTRODUCTION: Cardiovascular autonomic nervous system (CV-ANS) function is negatively impacted after concussion. The arterial baroreflex buffers pressor and depressor challenges through efferent modulation of cardiac chrono- and inotropism, and peripheral vascular tone. Baroreceptor sensitivity (BRS) reflects the capacity of the CV-ANS to accommodate dynamic metabolic demands in the periphery. The impact of concussion on BRS has yet to be defined.
METHODS: CV-ANS assessment (e.g., electrocardiogram and beat-to-beat SBP) was performed the seated upright position at rest within 48 hours (V1) of concussion and 1 week later (V2) in 10 intercollegiate male athletes with concussion and 10 non-injured male athletes. Changes in heart rate (HR), SBP, high and low frequency HR variability (HF- and LF-HRV, respectively), LF-SBP variability and BRS for increasing (BRSn-Up) and decreasing (BRSn-Dn) SBP excursions, and overall BRS (BRSn-Avg) were assessed for differences at V1 and V2.
RESULTS: The concussion (age: 20±1 years; height: 1.79±0.14 meters; weight: 83±10 kilograms) and control (age: 20±1 years; height: 1.78±0.10 meters; weight: 79±13 kilograms) groups were matched for demographics. Concussed athletes had a significantly reduced BRSn-Up, BRSn-Dn, and BRSn-Avg compared to controls at V1 or V2; these changes occurred without differences in conventional markers of CV-ANS function (e.g., HF-HRV, LF-HRV, LF-SBP), HR or SBP at either visit.
CONCLUSIONS: Reduced BRS is a post-concussive consequence of CV-ANS dysfunction during the first post-injury week. Because SBP was similar between groups, it may be speculated that reduced BRS was not afferent in origin, but represents a post-injury consequence of the central nervous system after injury.
Language: en |