Attenuated cardiovascular responses to the cold pressor test in concussed collegiate athletes

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 ¼ 20 6 2 years) who were within 7 days of diagnosis and 10 healthy control individuals (5 men, 5 women; age ¼ 24 6 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 ¼ 16 6 13 beats/min; P, .001) in healthy control participants but remained unchanged in concussed athletes (peak increase at 60 seconds ¼ 7 6 10 beats/min; P ¼ .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 6 7 mm Hg; P ¼ .048) in healthy control individuals (peak increase at 120 seconds ¼ 26 6 9 mm Hg; P, .001). Mean arterial pressure increased in concussed athletes at 90 seconds (8 6 8 mm Hg; P ¼ .003) and 120 seconds (12 6 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 ¼ 25 6 10 mm Hg and 8 6 8 mm Hg, respectively; P, .001). Conclusions: Recently concussed athletes had blunted cardiovascular responses to the CPT, which indicated sympathetic dysfunction.