Research Laboratory: Education, Motricité, Sport et Santé, EM2S, LR19JS01, High Institute of Sport and Physical Education, University of Sfax, Sfax, Tunisia.
Université de Lille, Université d'Artois, Université du Littoral Côte d'Opale, ULR 7369 - URePSSS - Unité de Recherche Pluridisciplinaire Sport, Santé, Société (URePSSS), Lille, France.
Eur J Appl Physiol. 2024 Jul;124(7):1991-2004. doi: 10.1007/s00421-024-05427-0. Epub 2024 Feb 19.
The present study aimed to characterize the exercise-induced neuromuscular fatigue and its possible links with cerebral and muscular oxygen supply and utilization to provide mechanistic insights into the reduced exercise capacity characterizing patients with end-stage renal disease (ESRD).
Thirteen patients with ESRD and thirteen healthy males (CTR group) performed a constant-force sustained isometric contraction at 50% of their maximal voluntary isometric contraction (MVC) until exhaustion. Quadriceps muscle activation during exercise was estimated from vastus lateralis, vastus medialis, and rectus femoris EMG. Central and peripheral fatigue were quantified via changes in pre- to postexercise quadriceps voluntary activation (ΔVA) and quadriceps twitch force (ΔQ) evoked by supramaximal electrical stimulation, respectively. To assess cerebral and muscular oxygenation, throughout exercise, near-infrared spectroscopy allowed investigation of changes in oxyhemoglobin (∆OHb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the prefrontal cortex and in the vastus lateralis muscle.
ESRD patients demonstrated lower exercise time to exhaustion than that of CTR (88.8 ± 15.3 s and 119.9 ± 14.6 s, respectively, P < 0.01). Following the exercise, MVC, Q, and VA reduction were similar between the groups (P > 0.05). There was no significant difference in muscle oxygenation (∆OHb) between the two groups (P > 0.05). Cerebral and muscular blood volume (∆THb) and oxygen extraction (∆HHb) were significantly blunted in the ESRD group (P < 0.05). A significant positive correlation was observed between time to exhaustion and cerebral blood volume (∆THb) in both groups (r = 0.64, P < 0.01).
These findings support cerebral hypoperfusion as a factor contributing to the reduction in exercise capacity characterizing ESRD patients.
本研究旨在描述运动诱导的神经肌肉疲劳及其与大脑和肌肉氧供应和利用的可能联系，为理解终末期肾病（ESRD）患者运动能力下降的机制提供依据。
13 名 ESRD 患者和 13 名健康男性（对照组）以 50%最大自主等长收缩（MVC）进行等长持续收缩，直至力竭。通过股外侧肌、股直肌和股中间肌的肌电图（EMG）估计运动过程中的股四头肌激活。通过测量最大电刺激后股四头肌主动激活（ΔVA）和股四头肌抽搐力（ΔQ）的变化，分别量化中枢和外周疲劳。为了评估大脑和肌肉的氧合，近红外光谱（NIRS）在整个运动过程中用于研究前额叶皮层和股外侧肌中氧合血红蛋白（∆OHb）、脱氧血红蛋白（∆HHb）和总血红蛋白（∆THb）的变化。
ESRD 患者的运动至力竭时间明显短于对照组（88.8±15.3s 和 119.9±14.6s，P<0.01）。两组在运动后 MVC、Q 和 VA 均显著降低（P>0.05）。两组之间肌肉氧合（∆OHb）没有显著差异（P>0.05）。但 ESRD 组大脑和肌肉血容量（∆THb）和氧摄取（∆HHb）明显减弱（P<0.05）。两组中，力竭时间与大脑血容量（∆THb）之间存在显著正相关（r=0.64，P<0.01）。
这些发现支持大脑低灌注是导致 ESRD 患者运动能力下降的因素之一。
