Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland.
Division of Sport and Exercise Sciences, Abertay University, Dundee, UK.
Respir Physiol Neurobiol. 2019 Nov;269:103258. doi: 10.1016/j.resp.2019.103258. Epub 2019 Jul 23.
We tested the hypothesis that type 2 diabetes (T2D) alters the profile of muscle fractional oxygen (O) extraction (near-infrared spectroscopy) during incremental cycle exercise. Seventeen middle-aged individuals with uncomplicated T2D and 17 controls performed an upright ramp test to exhaustion. The rate of muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration, Δ[HHb+Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against % power output (PO) and fitted with a double linear regression model. Peak oxygen uptake was significantly (P < 0.05) reduced in individuals with T2D. The %Δ[HHb+Mb]/%PO slope of the first linear segment of the double linear regression function was significantly (P < 0.05) steeper in T2D than controls (1.59 (1.14) vs 1.23 (0.51)). Both groups displayed a near-plateau in Δ[HHb+Mb] at an exercise intensity (%PO) not different amongst them. Such findings suggest that a reduced O delivery to active muscles is an important underlying cause of exercise intolerance during a maximum graded test in middle-aged individuals with T2D.
我们检验了一个假设，即 2 型糖尿病（T2D）改变了递增循环运动过程中肌肉氧分数提取（近红外光谱）的特征。17 名患有单纯 T2D 的中年人和 17 名对照者进行了直立斜坡测试直至力竭。股外侧肌的肌肉去氧（即去氧血红蛋白和肌红蛋白浓度，Δ[HHb+Mb]）曲线被归一化为 100%的反应，与功率输出（PO）的百分比作图，并拟合双线性回归模型。T2D 患者的峰值摄氧量显著降低（P<0.05）。双线性回归函数的第一段的%Δ[HHb+Mb]/%PO 斜率在 T2D 组中明显（P<0.05）高于对照组（1.59（1.14）对 1.23（0.51））。两组在运动强度（%PO）上的 Δ[HHb+Mb]均接近平台，两组之间无差异。这些发现表明，在中年 T2D 患者的最大分级测试中，向活跃肌肉输送的氧气减少是运动不耐受的一个重要潜在原因。
