Face cooling exposes cardiac parasympathetic and sympathetic dysfunction in recently concussed college athletes

Abstract

We tested the hypothesis that concussed college athletes (CA) have attenuated parasympathetic and sympathetic responses to face cooling (FC). Eleven symptomatic CA (age: 20 ± 2 years, 5 women) who were within 10 days of concussion diagnosis and 10 healthy controls (HC; age: 24 ± 4 years, 5 women) participated. During FC, a plastic bag filled with ice water (~0°C) was placed on the forehead, eyes, and cheeks for 3 min. Heart rate (ECG) and blood pressure (photoplethysmography) were averaged at baseline and every 60 sec during FC. High-frequency (HF) power was obtained from spectral analysis of the R-R interval. Data are presented as a change from baseline. Baseline heart rate (HC: 61 ± 12, CA: 57 ± 12 bpm; P = 0.69), mean arterial pressure (MAP) (HC: 94 ± 10, CA: 96 ± 13 mmHg; P = 0.74), and HF (HC: 2294 ± 2314, CA: 2459 ± 2058 msec2; P = 0.86) were not different between groups. Heart rate in HC decreased at 2 min (−7 ± 11 bpm; P = 0.02) but did not change in CA (P > 0.43). MAP increased at 1 min (HC: 12 ± 6, CA: 6 ± 6 mmHg), 2 min (HC: 21 ± 7, CA: 11 ± 7 mmHg), and 3 min (HC: 20 ± 6, CA: 13 ± 7 mmHg) in both groups (P < 0.01 for all) but the increase was greater at each interval in HC (P < 0.02). HF increased at 1 min (12354 ± 11489 msec2; P < 0.01) and 2 min (5832 ± 8002 msec2; P = 0.02) in HC but did not change in CA (P > 0.58). The increase in HF at 1 min was greater in HC versus CA (P < 0.01). These data indicate that symptomatic concussed patients have impaired cardiac parasympathetic and sympathetic activation.