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 with (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 mmHg; P =.048) in healthy control individuals (peak increase at 120 seconds = 26 ± 9 mmHg; P <.001). Mean arterial pressure increased in concussed athletes at 90 seconds (8 ± 8 mmHg; P =.003) and 120 seconds (12 ± 8 mmHg; 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 mmHg and 8 ± 8 mmHg, respectively; P <.001).
CONCLUSIONS: Recently concussed athletes had blunted cardiovascular responses to the CPT, which indicated sympathetic dysfunction.