Farzam Parisa, Starkweather Zack, Franceschini Maria A
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Physiol Rep. 2018 Apr;6(7):e13664. doi: 10.14814/phy2.13664.
There is a growing interest in monitoring muscle oxygen saturation (SmO ), which is a localized measure of muscle oxidative metabolism and can be acquired continuously and noninvasively using near-infrared spectroscopy (NIRS) methods. Most NIRS systems are cumbersome, expensive, fiber coupled devices, with use limited to lab settings. A novel, low cost, wireless, wearable has been developed for use in athletic training. In this study, we evaluate the advantages and limitations of this new simple continuous-wave (CW) NIRS device with respect to a benchtop, frequency-domain near-infrared spectroscopy (FDNIRS) system. Oxygen saturation and hemoglobin/myoglobin concentration in the exercising muscles of 17 athletic individuals were measured simultaneously with the two systems, while subjects performed an incremental test on a stationary cycle ergometer. In addition, blood lactate concentration was measured at the end of each increment with a lactate analyzer. During exercise, the correlation coefficients of the SmO and hemoglobin/myoglobin concentrations between the two systems were over 0.70. We also found both systems were insensitive to the presence of thin layers of varying absorption, mimicking different skin colors. Neither system was able to predict the athletes' lactate threshold power accurately by simply using SmO thresholds. Instead, the proprietary software of the wearable device was able to predict the athletes' lactate threshold power within half of one power increment of the cycling test. These results indicate this novel wearable device may provide a physiological indicator of athlete's exertion.
监测肌肉氧饱和度（SmO₂）的兴趣日益浓厚，肌肉氧饱和度是肌肉氧化代谢的局部测量指标，可使用近红外光谱（NIRS）方法连续、无创地获取。大多数NIRS系统笨重、昂贵且为光纤耦合设备，使用局限于实验室环境。已开发出一种新型、低成本、无线、可穿戴的设备用于运动训练。在本研究中，我们针对台式频域近红外光谱（FDNIRS）系统评估了这种新型简单连续波（CW）NIRS设备的优缺点。在17名运动员进行固定自行车测力计递增测试时，用这两种系统同时测量其运动肌肉中的氧饱和度以及血红蛋白/肌红蛋白浓度。此外，在每次递增结束时用乳酸分析仪测量血乳酸浓度。运动期间，两种系统之间的SmO₂以及血红蛋白/肌红蛋白浓度的相关系数超过0.70。我们还发现两种系统对模拟不同肤色的不同吸收薄层的存在均不敏感。两种系统均无法仅通过SmO₂阈值准确预测运动员的乳酸阈功率。相反，可穿戴设备的专有软件能够在骑行测试的一个功率增量的一半范围内预测运动员的乳酸阈功率。这些结果表明这种新型可穿戴设备可能提供运动员运动强度的生理指标。
