Cardiovascular Dynamics During The Cold Pressor Test In Recently Concussed College Athletes

Abstract

Concussion patients who are experiencing symptoms appear to have impaired cardiovascular responses during sympathoexcitatory tests such as handgrip exercise and head-up tilting. However, it is not known if impaired cardiovascular responses are present during a cold pressor test (CPT). PURPOSE: We tested the hypothesis that recently concussed college athletes would have a blunted cardiovascular response during a CPT. METHODS: Four college athletes (age: 19 ± 1 years, 2 women) who were within 7 days of concussion diagnosis and still reporting symptoms and four healthy controls (age: 27 ± 4 years, all men) underwent a CPT. During the CPT, the participant’s right hand was submerged in an ice slurry mixture for 120 seconds. Heart rate (ECG) and blood pressure (photoplethysmography) were continuously measured and averaged at baseline and every 30 seconds during the CPT. RESULTS: Heart rate was increased at 30 seconds (20 ± 5 bpm, P = 0.001) and 60 seconds (26 ± 13 bpm, P < 0.001) in the healthy controls but remained unchanged throughout the CPT in the concussed athletes (peak increase at 120 seconds: 10 ± 5 bpm, P = 0.257). Mean arterial pressure was elevated throughout the CPT in the healthy controls with a peak increase of 27 ± 6 mmHg at 120 seconds (P < 0.001). The peak increase in mean arterial pressure of 9 ± 6 mmHg in the concussed athletes was observed at 120 seconds, but did not reach statistical significance (P = 0.079). Systolic blood pressure was elevated at 60 seconds and throughout the remainder of the CPT in healthy controls reaching a peak increase of 28 ± 6 mmHg at 120 seconds (P < 0.001). Systolic blood pressure in concussed athletes did not increase at any point of the CPT (P > 0.196 for all time points). Diastolic blood pressure in healthy controls was elevated throughout the CPT and reached a peak increase at 120 seconds (21 ± 4 mmHg, P < 0.001). In concussed athletes, diastolic blood pressure was elevated only at 120 seconds (7 ± 5 mmHg, P = 0.014) of the CPT. CONCLUSIONS: These preliminary data show that recently concussed athletes have a blunted cardiovascular response to the CPT. These data support evidence indicating that concussed patients who are experiencing symptoms have impaired cardiovascular responses to sympathoexcitatory stimuli.