Fontolliet Timothée, Pichot Vincent, Bringard Aurélien, Fagoni Nazzareno, Adami Alessandra, Tam Enrico, Furlan Raffaello, Barthélémy Jean-Claude, Ferretti Guido
Départements d'Anesthésiologie, de Pharmacologie et des Soins Intensifs/des Neurosciences Fondamentales, Université de Genève, Geneva, Switzerland.
Système Nerveux Autonome-Epidémiologie, Physiologie, Ingénierie, Santé, EA 4607, Université Jean-Monnet, Saint-Étienne, France.
J Appl Physiol (1985). 2018 Dec 1;125(6):1804-1811. doi: 10.1152/japplphysiol.00619.2018. Epub 2018 Oct 11.
We performed the first analysis of heart rate variability (HRV) at rest and during exercise under full autonomic blockade on the same subjects, to test the conjecture that vagal tone withdrawal occurs at exercise onset. We hypothesized that between rest and exercise there would be ) no differences in total power (P) under parasympathetic blockade, ) a P fall under β-sympathetic blockade, and ) no differences in P under blockade of both autonomic nervous system branches. Seven men [24 (3) yr, mean (SD)] performed 5-min cycling (80 W) supine, preceded by 5-min rest during control and with administration of atropine, metoprolol, and atropine + metoprolol (double blockade). Heart rate and arterial blood pressure were continuously recorded. HRV and blood pressure variability were determined by power spectral analysis, and baroreflex sensitivity was determined by the sequence method. At rest, P and the powers of low- and high-frequency components of HRV (LF and HF, respectively) were dramatically decreased with atropine and double blockade compared with control and metoprolol, with no effects on LF-to-HF ratio and on the normalized LF (LFnu) and HF (HFnu). During exercise, patterns were the same as at rest. Comparing exercise with rest, P varied as hypothesized. For systolic and diastolic blood pressure, resting P was the same in all conditions. During exercise, in all conditions, P was lower than in control. Baroreflex sensitivity decreased under atropine and double blockade at rest and under control and metoprolol during exercise. The results support the hypothesis that vagal suppression determined disappearance of HRV during exercise. This study provides the first demonstration, by systematic analysis of heart rate variability at rest and during exercise under full autonomic blockade on the same subjects, that suppression of vagal activity is responsible for the disappearance of spontaneous heart rate variability during exercise. This finding supports previous hypotheses on the role of vagal withdrawal in the control of the rapid cardiovascular response at exercise onset.
我们在同一受试者身上进行了首次关于完全自主神经阻滞状态下静息和运动时心率变异性（HRV）的分析，以检验运动开始时迷走神经张力降低这一推测。我们假设，在静息和运动之间，) 副交感神经阻滞后总功率（P）无差异，) β-交感神经阻滞后P下降，以及) 自主神经系统两个分支均被阻滞后P无差异。7名男性[24（3）岁，均值（标准差）]在仰卧位进行5分钟的骑行（80瓦），之前在对照状态下静息5分钟，并分别给予阿托品、美托洛尔以及阿托品+美托洛尔（双重阻滞）。连续记录心率和动脉血压。通过功率谱分析确定HRV和血压变异性，通过序列法确定压力反射敏感性。静息时，与对照和美托洛尔相比，阿托品和双重阻滞使P以及HRV低频和高频成分的功率（分别为LF和HF）显著降低，对LF与HF比值、归一化LF（LFnu）和HF（HFnu）无影响。运动期间，模式与静息时相同。将运动与静息进行比较，P变化符合假设。对于收缩压和舒张压，静息时P在所有条件下均相同。运动期间，在所有条件下，P均低于对照。静息时阿托品和双重阻滞以及运动时对照和美托洛尔状态下压力反射敏感性均降低。结果支持运动期间迷走神经抑制导致HRV消失这一假设。本研究通过对同一受试者在完全自主神经阻滞状态下静息和运动时的心率变异性进行系统分析，首次证明迷走神经活动的抑制是运动期间自发性心率变异性消失的原因。这一发现支持了先前关于运动开始时迷走神经张力降低在快速心血管反应控制中作用的假设。
