Hayashi N, Ishihara M, Tanaka A, Osumi T, Yoshida T
Faculty of Health and Sports Sciences, Osaka University Toyonaka, Japan.
Eur J Appl Physiol Occup Physiol. 1997;76(5):394-9. doi: 10.1007/s004210050267.
We examined whether the diving reflex without breath-holding (face immersion alone) increases vagal activity, as determined by heart rate variability. A group of 15 men [mean age 20 (SD 3) years, height 172 (SD 5) cm, body mass 68 (SD 9) kg] performed 12 trials at various breathing frequencies (5, 10, 15, 20, 30 breaths x min(-1) and uncontrolled breath) with or without face immersion. The R-R intervals of the ECG and gas exchange variables were recorded during the 2 min of each trial. The subjects immersed their faces in 8 10 degrees C water while breathing through a short snorkel. The subject sat in the same position either with or without face immersion. The mean R-R interval (RRmean), standard deviations (SD[RR]) and coefficient of variance (CV[RR]) of the R-R interval were calculated from the R-R intervals during 30-120 s. The face immersion significantly increased SD(RR) and CV(RR) (P < 0.05), and increased RRmean (P < 0.05) at 20 breaths x min(-1). Face immersion itself had no effect on oxygen uptake, tidal volume, end-tidal O2 and CO2 partial pressures. The diving reflex without breath-holding increased the heart rate variability, indicating that face immersion alone increases vagal activity.
我们通过心率变异性来研究不屏气的潜水反射（仅面部浸入水中）是否会增加迷走神经活动。一组15名男性[平均年龄20（标准差3）岁，身高172（标准差5）厘米，体重68（标准差9）千克]在不同呼吸频率（5、10、15、20、30次呼吸×分钟⁻¹以及非控制呼吸）下进行了12次试验，试验过程中有或没有面部浸入水中的情况。在每次试验的2分钟内记录心电图的R-R间期以及气体交换变量。受试者通过短呼吸管呼吸时将面部浸入8至10摄氏度的水中。受试者在有或没有面部浸入水中的情况下都坐在相同位置。根据30至120秒内的R-R间期计算R-R间期的平均R-R间期（RRmean）、标准差（SD[RR]）和变异系数（CV[RR]）。面部浸入显著增加了SD(RR)和CV(RR)（P<0.05），并在20次呼吸×分钟⁻¹时增加了RRmean（P<0.05）。面部浸入本身对摄氧量、潮气量、呼气末O₂和CO₂分压没有影响。不屏气的潜水反射增加了心率变异性，表明仅面部浸入水中就会增加迷走神经活动。
