Strano S, Lino S, Calcagnini G, Di Virgilio V, Ciardo R, Cerutti S, Calcagnini G, Caselli G
The Department of Clinical Pathophysiology, University of Rome La Sapienza, Italy.
Med Sci Sports Exerc. 1998 Feb;30(2):215-9. doi: 10.1097/00005768-199802000-00007.
Studies using spectral analysis of cardiovascular variability as a noninvasive means for assessing autonomic nervous system activity have provided controversial results in athletes. One reason is that a slow breathing rate--a common feature in athletes--affects spectral estimation because it causes the low-frequency (LF) and high-frequency (HF) components to overlap. Low-frequency power increases during sympathetic activation; high-frequency corresponds to respiratory sinus arrhythmia. In this study, to assess how controlled respiration influences autonomic nervous system activity, we determined the effect of controlled and uncontrolled breathing conditions on cardiovascular variability. Our aim was to identify a standard respiratory rate for spectral estimation of cardiovascular neural control in athletes. During electrocardiographic recordings, subjects lay supine and breathed at their spontaneous frequency and at rates of 15, 12, and 10 to 14 (random) breaths x min(-1). Uncontrolled and random breathing rates significantly altered spectral sympathetic indices; conversely, 15 and 12 breaths x min(-1) redistributed respiratory related power through the HF, thus yielding correct LF power estimation. None of the breathing conditions significantly changed mean heart rate, arterial blood pressure, or spectral total power of cardiovascular variability. In conclusion, when power spectral analysis is used for assessing autonomic activity in athletes, respiration should be standardized at 15 breaths x min(-1). Controlled respiration at this rate leaves autonomic nervous system activity unchanged.
利用心血管变异性频谱分析作为评估自主神经系统活动的非侵入性手段的研究，在运动员中得出了有争议的结果。一个原因是呼吸频率缓慢——运动员的一个常见特征——会影响频谱估计，因为它会导致低频（LF）和高频（HF）成分重叠。交感神经激活时低频功率增加；高频对应于呼吸性窦性心律失常。在本研究中，为了评估控制性呼吸如何影响自主神经系统活动，我们确定了控制性和非控制性呼吸条件对心血管变异性的影响。我们的目的是确定运动员心血管神经控制频谱估计的标准呼吸频率。在心电图记录期间，受试者仰卧，以自发频率以及15、12和10至14次（随机）呼吸·分钟⁻¹的频率呼吸。非控制性和随机呼吸频率显著改变了频谱交感神经指标；相反，15和12次呼吸·分钟⁻¹通过高频重新分配了与呼吸相关的功率，从而得出正确的低频功率估计值。没有一种呼吸条件能显著改变平均心率、动脉血压或心血管变异性的频谱总功率。总之，当使用功率谱分析评估运动员的自主活动时，呼吸应标准化为15次呼吸·分钟⁻¹。以该频率进行控制性呼吸可使自主神经系统活动保持不变。
