Integrative Laboratory of Exercise and Applied Physiology, Department of Health, Kinesiology, and Sport, College of Education and Professional Studies, University of South Alabama, Mobile, Alabama, United States.
Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, Alabama, United States.
J Appl Physiol (1985). 2023 Jul 1;135(1):3-14. doi: 10.1152/japplphysiol.00174.2023. Epub 2023 May 18.
Men and women exhibit different near-infrared spectroscopy (NIRS) outcomes in response to vascular occlusion tests (VOT), which may be due to phenotypic characteristics or different degrees of desaturation during ischemia. The minimum skeletal muscle tissue oxygenation (StO) observed during a VOT may be the primary determinant of reactive hyperemic (RH) responses. Our purpose was to determine the contribution StO and participant characteristics including adipose tissue thickness (ATT), lean body mass (LBM), muscular strength, and limb circumference to NIRS-derived indexes of RH. Also, we aimed to determine if matching StO would eliminate NIRS-VOT sex differences. Thirty-one young adults completed one or two VOTs during which the vastus lateralis was continuously assessed for StO. The men and women each completed a standard VOT with a 5-min ischemic phase. The men completed a second VOT with a shortened ischemic phase to produce a matching StO to the minimum of the women observed during the standard VOT. Mean sex differences were determined with tests, and relative contributions were assessed with multiple regression and model comparison approaches. During the 5-min ischemic phase, the men exhibited greater upslopes (1.97 ± 0.66 vs. 1.23 ± 0.59%·s) and greater StO than the women (80.3 ± 4.17 vs. 76.2 ± 2.86%). Analysis revealed StO was a greater contributor to upslope than sex and/or ATT. For StO, sex was the only significant predictor ( = 0.26, men ∼4.09% > women). Experimentally matching StO did not eliminate the sex differences in upslope or StO, suggesting that characteristics other than the degree of desaturation primarily provoke sex differences in RH. Men exhibit greater values of reactive hyperemia than women even when controlling for the magnitude of desaturation during transient ischemia. Factors other than the ischemic vasodilatory stimulus, such as skeletal muscle mass and quality, likely provoke the commonly reported sex differences in reactive hyperemia measured by near-infrared spectroscopy.
男性和女性在血管闭塞试验（VOT）中表现出不同的近红外光谱（NIRS）结果，这可能是由于表型特征或缺血期间不同程度的饱和度下降。VOT 期间观察到的最小骨骼肌组织氧合（StO）可能是反应性充血（RH）反应的主要决定因素。我们的目的是确定 StO 和参与者特征（包括脂肪组织厚度（ATT）、瘦体重（LBM）、肌肉力量和肢体周长）对 NIRS 衍生 RH 指标的贡献。此外，我们旨在确定是否匹配 StO 会消除 NIRS-VOT 的性别差异。31 名年轻人完成了一次或两次 VOT，在此期间连续评估股外侧肌的 StO。男性和女性都完成了一个标准的 VOT，缺血期为 5 分钟。男性完成了第二次 VOT，缺血期缩短，以产生与女性在标准 VOT 中观察到的最小值相匹配的 StO。采用 t 检验确定平均性别差异，采用多元回归和模型比较方法评估相对贡献。在 5 分钟缺血期，男性的上升斜率（1.97±0.66%·s 比 1.23±0.59%·s）和 StO 大于女性（80.3±4.17% 比 76.2±2.86%）。分析表明，StO 对上升斜率的贡献大于性别和/或 ATT。对于 StO，性别是唯一显著的预测因子（ = 0.26，男性~4.09%>女性）。实验性地匹配 StO 并没有消除上升斜率或 StO 的性别差异，这表明除了饱和度下降程度之外，其他特征主要引起 RH 的性别差异。即使在控制短暂缺血期间饱和度下降的程度时，男性的反应性充血值也大于女性。除了缺血性血管扩张刺激之外的其他因素，如骨骼肌质量和质量，可能会引起近红外光谱测量的常见的反应性充血性别差异。
