Int J Sports Physiol Perform. 2020 May 1;15(5):714-719. doi: 10.1123/ijspp.2019-0168.
To assess tissue oxygenation, along with metabolic and physiological responses during blood flow restriction (BFR, bilateral vascular occlusion) and systemic hypoxia conditions during submaximal leg- versus arm-cycling exercise.
In both legs and arms, 4 randomized sessions were performed (normoxia 400 m, fraction of inspired oxygen [FIO2] 20.9% and normobaric hypoxia 3800 m, FIO2 13.1% [0.1%]; combined with BFR at 0% and 45% of resting pulse elimination pressure). During each session, a single 6-minute steady-state submaximal exercise was performed to measure physiological changes and oxygenation (near-infrared spectroscopy) of the muscle tissue in both the vastus lateralis (legs) and biceps brachii (arms).
Total hemoglobin concentration ([tHb]) was 65% higher (P < .001) in arms versus legs, suggesting that arms had a greater blood perfusion capacity than legs. Furthermore, there were greater changes in tissue blood volume [tHb] during BFR compared with control conditions (P = .017, F = 5.45). The arms elicited 7% lower tissue saturation (P < .001) and were thus more sensitive to the hypoxia-induced reduction in oxygen supply than legs, no matter the condition. This indicates that legs and arms may elicit different regulatory hemodynamic mechanisms (ie, greater blood flow in arms) for limiting the decreased oxygen delivery during exercise with altered arterial oxygen content.
The combination of BFR and/or hypoxia led to increased [tHb] in both limbs likely due to greater vascular resistance; further, arms were more responsive than legs. This possibly influences the maintenance of oxygen delivery and enhances perfusion pressure, suggesting greater vascular reactivity in arms than in legs.
评估血流限制（双侧血管闭塞）和次最大腿部与手臂循环运动期间全身缺氧条件下的组织氧合以及代谢和生理反应。
在双腿和双臂中，进行了 4 个随机分组（常氧 400m，吸入氧分数[FIO2]20.9%和常压缺氧 3800m，FIO2 13.1%[0.1%]；与 0%和 45%的静息脉搏消除压力的血流限制相结合）。在每次运动期间，进行了一次 6 分钟的稳定次最大稳态运动，以测量肌肉组织的生理变化和氧合（近红外光谱），测量部位分别为股外侧肌（腿部）和肱二头肌（手臂）。
与腿部相比，手臂的总血红蛋白浓度（[tHb]）高 65%（P<0.001），这表明手臂的血液灌注能力大于腿部。此外，与对照条件相比，血流限制期间组织血容量[tHb]的变化更大（P=0.017，F=5.45）。手臂的组织饱和度降低了 7%（P<0.001），因此手臂对缺氧引起的氧供减少比腿部更敏感，无论哪种情况都是如此。这表明，在运动期间，腿部和手臂可能会引发不同的调节性血液动力学机制（即手臂中血流增加）来限制动脉血氧含量改变导致的氧输送减少。
血流限制和/或缺氧的组合导致四肢的[tHb]增加，这可能是由于血管阻力增加所致；此外，手臂的反应性比腿部更强。这可能会影响氧输送的维持，并增强灌注压，表明手臂的血管反应性大于腿部。
