Integrated Evaluation of Macro- and Microvascular Function in Human Limbs Using Simultaneous Application of FMD and NIRS Techniques

PURPOSE: Endothelial dysfunction is an early indicator of cardiovascular disease. Regular exercise improves vascular function, highlighting the need for accurate assessment of exercise-induced vascular adaptations. This paper introduces a simultaneous evaluation method combining flow-mediated dilation (FMD) using Doppler ultrasound and vascular occlusion testing (VOT) using near-infrared spectroscopy (NIRS) to assess vascular responses at both macrovascular and microvascular levels.METHODS: We present a unified assessment protocol integrating Doppler ultrasound-based FMD and near-infrared spectroscopy-based vascular occlusion testing (NIRS-VOT). This paper systematically outlines the experimental procedures, including participant preparation, equipment configuration, measurement protocols, data analysis methods, and clinical interpretation strategies. To ensure the accuracy and reproducibility of vascular function assessment, standardized guidelines are provided for subject preparation (e.g., fasting, medication restriction), ultrasound and NIRS probe placement, and occlusion parameters such as pressure and duration.RESULTS: This combined approach provides a non-invasive means to assess vascular function at both the macrovascular and microvascular levels, while also capturing their functional interactions.CONCLUSIONS: The proposed method enables integrated assessment of vascular adaptations across multiple levels, offering insights into the physiological mechanisms underlying exercise-induced vascular improvements. It may serve as a valuable tool in exercise research and clinical evaluation of vascular health.