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

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 msec 2 ; 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 msec 2 ; P  < 0.01) and 2 min (5832 ± 8002 msec 2 ; 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.