We investigated the role of the exercise pressor reflex (EPR) in regulating the haemodynamic response to locomotor exercise. Eight healthy participants (23 ± 3 years, ${\dot{V}}_{{\mathrm{O}}_2\max }$: 49 ± 6 ml/kg/min) performed constant-load cycling exercise (∼36/43/52/98% ${\dot{V}}_{{\mathrm{O}}_2\max }$; 4 min each) without (CTRL) and with (FENT) lumbar intrathecal fentanyl attenuating group III/IV locomotor muscle afferent feedback and, thus, the EPR. To avoid different respiratory muscle metaboreflex and arterial chemoreflex activation during FENT, subjects mimicked the ventilatory response recorded during CTRL. Arterial and leg perfusion pressure (femoral arterial and venous catheters), femoral blood flow (Doppler-ultrasound), microvascular quadriceps blood flow index (indocyanine green), cardiac output (inert gas breathing), and systemic and leg vascular conductance were quantified during exercise. There were no cardiovascular and ventilatory differences between conditions at rest. Pulmonary ventilation, arterial blood gases and oxyhaemoglobin saturation were not different during exercise. Furthermore, cardiac output (−2% to −12%), arterial pressure (−7% to −15%) and leg perfusion pressure (−8% to −22%) were lower, and systemic (up to 16%) and leg (up to 27%) vascular conductance were higher during FENT compared to CTRL. Leg blood flow, microvascular quadriceps blood flow index, and leg O₂-transport and utilization were not different between conditions (P > 0.5). These findings reflect a critical role of the EPR in the autonomic control of the heart, vasculature and, ultimately, arterial pressure during locomotor exercise. However, the lack of a net effect of the EPR on leg blood flow challenges the idea of this cardiovascular reflex as a key determinant of leg O₂-transport during locomotor exercise in healthy, young individuals.

我们研究了运动加压反射 （EPR） 在调节对运动运动的血流动力学反应中的作用。8 名健康参与者 （23 ± 3 岁， ${\dot{V}}_{{\mathrm{O}}_2\max }$ ： 49 ± 6 ml/kg/min） 进行恒负荷循环运动 （∼36/43/52/98% ${\dot{V}}_{{\mathrm{O}}_2\max }$ ;每人 4 分钟） 无 （CTRL） 和有 （FENT） 腰椎鞘内芬太尼衰减组 III/IV 运动肌传入反馈，因此，EPR。为避免 FENT 期间不同的呼吸肌代谢反射和动脉化学反射激活，受试者模拟了 CTRL 期间记录的通气反应。动脉和腿部灌注压（股动脉和静脉导管）、股骨血流（多普勒超声）、微血管股四头肌血流指数（吲哚菁绿）、心输出量（惰性气体呼吸）以及运动期间的全身和腿部血管电导率。静息时的情况之间没有心血管和通气差异。运动时肺通气、动脉血气和氧合血红蛋白饱和度没有差异。此外，与 CTRL 相比，FENT 期间的心输出量（-2% 至 -12%）、动脉压（-7% 至 -15%）和腿部灌注压（-8% 至 -22%）较低，全身性（高达 16%）和腿部（高达 27%）血管电导率较高。腿部血流、微血管股四头肌血流指数和腿部 O₂ 运输和利用在不同条件下没有差异 （P> 0.5）。这些发现反映了 EPR 在运动运动期间心脏、脉管系统以及最终动脉压的自主神经控制中的关键作用。 然而，EPR 对腿部血流缺乏净效应，这挑战了这种心血管反射作为健康年轻人运动运动期间腿部 O₂ 运输的关键决定因素的观点。