Cardiovascular reactivity to and recovery from cold face test

Abstract

The purpose of this study was to investigate reactivity and recovery to primarily parasympathetic stimulation by cold face test.Sixty five students with a mean age of 20.61±0.13 years take part in the study (86% women, 14% men). They were studied in the morning hours in a quiet room at a comfortable temperature. Time domain (SDNN, RMSSD, pNN50), frequency domain (TP, HF, VLF, LF and LF/HF ratio) and nonlinear (SD1, SD2, ApEn, SampEn, D2, DFA1, DFA2) parameters of HRV were obtained from all participants for 5 minutes before, 5 minutes during and 5 minutes after cold face test (0–1 °C cold compresses) in a supine position. Statistical analysis was performed using Mann‐Whitney test.Heart rate during cold face test was significantly lower than that during rest period (74.03±1.26 vs 76.74±1.21 beat/min, p=0.006). After cold face test cessation heart rate displayed significant decrease compared to cold face test period (71.96±1.17 vs 74.03±1.26 beat/min, p=0.001). Time domain parameters were found to be higher during cold face test than that during rest (SDNN: 52.6±2.85 vs 43.61±2.23 ms, p=0.006; RMSSD: 59.87±4.08 vs 44.99±2.93 ms, p=0.001 and pNN50: 30.49±2.38 vs 22.07±2.13 %, p=0.003). During recovery period time domain parameters remain to be higher, than that during rest: SDNN – 47.97±2.29 ms, RMSSD – 52.16±3.35 ms, pNN50 – 27.24±2.38%.There was no differences during rest period, cold face test and recovery period in TP (2097.89±249.98 vs 2517.24±301.8 vs 2176.12±204 ms2, p=0.744), VLF (83.59±9.99 vs 92.44±12.21 vs 88.33±7.85 ms2, p=0.359), LF (932.86±107.70 vs 1024.98±132.06 ms2, vs 928.54±83.35, p=0.896). High frequency parameter was significantly higher during cold face test than that during rest (1395.36±184.39 vs 1078.11±143.13 ms2, p=0.013). After cold test HF parameter was 1156.11±129.74 ms2(p>0.05).Nonlinear measures were significantly higher during cold face test than that during rest (SD1: 42.39±2.89 vs 31.83±2.07 ms, p=0.001; SD2: 60.52±3.04 vs 52.45±2.50 ms, p=0.025). During recovery period nonlinear parameters remain to be higher, than that during rest: SD1 – 36.92±2.29 ms, SD2 – 56.34±2.44 ms, pNN50 – 27.24±2.38%. ApEn and DFA1 were significantly lower during cold face test than that during rest (respectively, 1.15±0.01 vs 1.40±0.01 and 0.87±0.03 vs 1.01±0.02, p<0.001). During recovery period ApEn was 1.37±0.01 and DFA1 was 0.96±0.03.The other HRV parameters including D2, LF/HF ratio, pLF, pHF, SampEn, DFA2 were not significantly different.These results suggest that cold face test has been associated with increased vagal cardiac control and decrease entropy and DFA1.