Attenuated Cardiovascular Responses to the Cold Pressor Test in Concussed Collegiate Athletes.

ABSTRACT

CONTEXT Cardiovascular responses to the cold pressor test (CPT) provide information regarding sympathetic function. OBJECTIVE: To determine if recently concussed collegiate athletes had blunted cardiovascular responses during the CPT. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 10 symptomatic concussed collegiate athletes (5 men, 5 women; age = 20 ± 2 years) who were within 7 days of diagnosis and 10 healthy control individuals (5 men, 5 women; age = 24 ± 4 years). INTERVENTION(S) The participants' right hands were submerged in agitated ice water for 120 seconds (CPT). MAIN OUTCOME MEASURE(S) Heart rate and blood pressure were continuously measured and averaged at baseline and every 30 seconds during the CPT. RESULTS: Baseline heart rate and mean arterial pressure were not different between groups. Heart rate increased throughout 90 seconds of the CPT (peak increase at 60 seconds = 16 ± 13 beats/min; P < .001) in healthy control participants but remained unchanged in concussed athletes (peak increase at 60 seconds = 7 ± 10 beats/min; P = .08). We observed no differences between groups for the heart rate response (P > .28). Mean arterial pressure was elevated throughout the CPT starting at 30 seconds (5 ± 7 mm Hg; P = .048) in healthy control individuals (peak increase at 120 seconds = 26 ± 9 mm Hg; P < .001). Mean arterial pressure increased in concussed athletes at 90 seconds (8 ± 8 mm Hg; P = .003) and 120 seconds (12 ± 8 mm Hg; P < .001). Healthy control participants had a greater increase in mean arterial pressure starting at 60 seconds (P < .001) and throughout the CPT than concussed athletes (peak difference at 90 seconds = 25 ± 10 mm Hg and 8 ± 8 mm Hg, respectively; P < .001). CONCLUSIONS: Recently concussed athletes had blunted cardiovascular responses to the CPT, which indicated sympathetic dysfunction.