Perini R, Milesi S, Biancardi L, Pendergast D R, Veicsteinas A
Cattedra di Fisiologia Umana, Dipartimento di Scienze Biomediche e Biotecnologie, Università di Brescia, Italy.
Eur J Appl Physiol Occup Physiol. 1998 Mar;77(4):326-32. doi: 10.1007/s004210050341.
Power spectrum analysis of heart-rate variability was made in seven men [mean age 22 (SEM 1) years] in head-out water immersion (W) and in air (A, control) at rest and during steady-state cycling to maximal intensity (maximum oxygen uptake, VO2max). At rest W resulted in a trebled increase in the total power (P < 0.05), coupled with minimal changes in the power (as a percentage of the total) of the high frequency peak (HF, centred at 0.26 Hz; 18% vs 28%) and of the low frequency peak (LF, 0.1 Hz; 24% vs 32%). A third peak at about 0.03 Hz (very low frequency, VLF) represented the remaining power both in W and A. These changes as a whole indicated that immersion caused a vagal dominance in cardiac autonomic interaction, due to the central pooling of blood and/or the pressure of water on the trunk. Exercise caused a decrease in the total power in W and A. The LF% did not change up to about 50% V02max, thereafter decreasing towards nil in both conditions. The HF% decreased in similar ways in W and A to about half at 55%-60% VO2max and then increased to reach 1.5 times the resting values at VO2max. The central frequency of HF increased linearly with oxygen uptake, showing a tendency to be higher in W than in A at medium to high intensities. The VLF% remained unchanged. The lack of differences in the LF peak between W and A during exercise would suggest that blood distribution had no effect on the readjustments in control mechanisms of arterial pressure. On the other hand, the findings of similar HF powers and the very similar values for ventilation in W and A confirmed the direct effect of the respiratory activity in heart rate modulation during exercise.
对7名男性（平均年龄22岁（标准误1岁））进行了心率变异性的功率谱分析。在静息状态以及稳态骑行至最大强度（最大摄氧量，VO₂max）时，分别测量他们头部露出水面的水中浸泡状态（W）和空气中（A，对照）的情况。静息时，水中浸泡导致总功率增加两倍（P < 0.05），同时高频峰值（HF，中心频率为0.26 Hz；占总功率的比例从18%变为28%）和低频峰值（LF，0.1 Hz；占总功率的比例从24%变为32%）的功率（占总功率的百分比）变化极小。在水中浸泡和空气中，约0.03 Hz处的第三个峰值（极低频，VLF）代表其余功率。总体而言，这些变化表明，由于血液向中心集中和/或水对躯干的压力，浸泡导致心脏自主神经相互作用中迷走神经占主导。运动导致水中浸泡和空气中的总功率均下降。在达到约50% VO₂max之前，低频百分比（LF%）没有变化，此后在两种情况下均降至零。高频百分比（HF%）在水中浸泡和空气中以相似方式下降，在55%-60% VO₂max时降至约一半，然后在VO₂max时增加至静息值的1.5倍。高频的中心频率随摄氧量呈线性增加，在中高强度时显示出水中浸泡状态下高于空气中的趋势。极低频百分比（VLF%）保持不变。运动期间水中浸泡和空气中低频峰值无差异，这表明血液分布对动脉压控制机制的重新调整没有影响。另一方面，水中浸泡和空气中高频功率相似以及通气值非常相似的结果，证实了运动期间呼吸活动对心率调节的直接影响。
