Department of Neurosciences, Biomedicine, and Movement, University of Verona, Verona, Italy.
Department of Internal Medicine, University of Utah, 500 Foothill Drive, Salt Lake City, UT, 84148, USA.
Eur J Appl Physiol. 2023 Aug;123(8):1751-1762. doi: 10.1007/s00421-023-05186-4. Epub 2023 Apr 4.
Previous studies in animal models showed that exercise-induced metabolites accumulation may sensitize the mechanoreflex-induced response. The aim of this study was to assess whether the magnitude of the central hemodynamic and ventilatory adjustments evoked by isolated stimulation of the mechanoreceptors in humans are influenced by the prior accumulation of metabolic byproducts in the muscle. 10 males and 10 females performed two exercise bouts consisting of 5-min of intermittent isometric knee-extensions performed 10% above the previously determined critical force. Post-exercise, the subjects recovered for 5 min either with a suprasystolic circulatory occlusion applied to the exercised quadriceps (PECO) or under freely-perfused conditions (CON). Afterwards, 1-min of continuous passive leg movement was performed. Central hemodynamics, pulmonary data, and electromyography from exercising/passively-moved leg were recorded throughout the trial. Root mean square of successive differences (RMSSD, index of vagal tone) was also calculated. Δpeak responses of heart rate (ΔHR) and ventilation ([Formula: see text]) to passive leg movement were higher in PECO compared to CON (ΔHR: 6 ± 5 vs 2 ± 4 bpm, p = 0.01; 3.9 ± 3.4 vs 1.9 ± 1.7 L min, p = 0.02). Δpeak of mean arterial pressure (ΔMAP) was significantly different between conditions (5 ± 3 vs - 3 ± 3 mmHg, p < 0.01). Changes in RMSSD with passive leg movement were different between PECO and CON (p < 0.01), with a decrease only in the former (39 ± 18 to 32 ± 15 ms, p = 0.04). No difference was found in all the other measured variables between conditions (p > 0.05). These findings suggest that mechanoreflex-mediated increases in HR and [Formula: see text] are sensitized by metabolites accumulation. These responses were not influenced by biological sex.
先前的动物模型研究表明，运动引起的代谢产物积累可能会使机械感受器引起的反应敏感化。本研究旨在评估在人类中，单独刺激机械感受器引起的中枢血液动力学和通气调整的幅度是否受到肌肉中代谢副产物先前积累的影响。10 名男性和 10 名女性进行了两次运动，包括 5 分钟的间歇性等长膝关节伸展运动，强度为先前确定的临界力的 10%以上。运动后，受试者在股四头肌施加超射循环闭塞（PECO）或自由灌注条件（CON）下恢复 5 分钟。之后，进行 1 分钟的连续被动腿部运动。整个试验过程中记录中枢血液动力学、肺部数据和运动/被动运动腿部的肌电图。还计算了连续差异均方根（RMSSD，迷走神经张力指数）。与 CON 相比，PECO 中被动腿部运动时的心率（ΔHR）和通气量（[Formula: see text]）的峰值反应更高（ΔHR：6±5 比 2±4 bpm，p=0.01；3.9±3.4 比 1.9±1.7 L min，p=0.02）。条件之间的平均动脉压（ΔMAP）峰值差异显著（5±3 比-3±3 mmHg，p<0.01）。PECO 和 CON 之间的被动腿部运动时 RMSSD 的变化不同（p<0.01），仅在前一种情况下下降（39±18 至 32±15 ms，p=0.04）。两种条件之间在所有其他测量变量上均未发现差异（p>0.05）。这些发现表明，机械感受器介导的 HR 和[Formula: see text]增加被代谢产物积累敏感化。这些反应不受生物性别影响。
