Blood lactate concentration is an established circulating biomarker for measuring muscle acidity and can be evaluated for monitoring endurance, training routines, or athletic performance. Sweat is an alternative biofluid that may serve similar purposes and offers the advantage of noninvasive collection and continuous monitoring. The relationship between blood lactate and dynamic sweat biochemistry for wearable engineering applications in physiological fitness remains poorly defined. Here, we developed a microfluidic wearable band with an integrated colorimetric timer and biochemical assays that temporally captures sweat and measures pH and lactate concentration. A colorimetric silver nanoplasmonic assay was used to measure the concentration of lactate, and dye-conjugated SiO 2 nanoparticle–agarose composite materials supported dynamic pH analysis. We evaluated these sweat biomarkers in relation to blood lactate in human participant studies during cycling exercise of varying intensity. Iontophoresis-generated sweat pH from regions of actively working muscles decreased with increasing heart rate during exercise and was negatively correlated with blood lactate concentration. In contrast, sweat pH from nonworking muscles did not correlate with blood lactate concentration. Changes in sweat pH and blood lactate were observed in participants who did not regularly exercise but not in individuals who regularly exercised, suggesting a relationship to physical fitness and supporting further development for noninvasive, biochemical fitness evaluations.

中文翻译：

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皮肤界面微流体平台支持人体运动期间的动态汗液生化分析


血乳酸浓度是一种用于测量肌肉酸度的既定循环生物标志物，可用于监测耐力、训练常规或运动表现。汗液是一种替代生物流体，可用于类似目的，并具有非侵入性收集和连续监测的优点。可穿戴工程应用在生理健康方面的血乳酸和动态汗液生物化学之间的关系仍然不明确。在这里，我们开发了一种微流体可穿戴手环，带有集成的比色计时器和生化检测，可暂时捕获汗水并测量 pH 值和乳酸浓度。比色银纳米等离激元测定用于测量乳酸浓度，染料缀合的 SiO 2 纳米颗粒-琼脂糖复合材料支持动态 pH 分析。我们在不同强度的自行车运动期间的人类参与者研究中评估了这些汗液生物标志物与血乳酸的关系。活跃工作的肌肉区域的离子电渗疗法产生的汗液 pH 值随着运动期间心率的增加而降低，并且与血乳酸浓度呈负相关。相比之下，非工作肌肉的汗液 pH 值与血乳酸浓度无关。在不经常锻炼的参与者中观察到汗液 pH 值和血乳酸的变化，但在经常锻炼的人中却没有观察到，这表明与身体健康有关，并支持进一步开发无创生化健康评估。