Wearable Devices for Studying Microvascular Reactivity - It Is Feasible?

We investigate what information can be obtained on daily changes in microcirculation using wearable technologies in out-of hospital or laboratory setting. The pulse wave, electrocardiogram, body temperature and blood pressure data obtained from seven days with normal physical activity was compared with data from seven days with 50% increase in physical activity. The number of steps and heart rate during daily activities were acquired using an electronic wrist watch. Radial artery and big toe digital artery pulse wave signals, wrist and big toe skin temperature, heart rate variability, were analyzed. The sympathetic nervous system influence on microcirculation was evaluated using frequency domain analysis of heart rate variability. The plantar signal was more influenced by movements artifact than pulse wave signal from radial artery. Low frequency component and ratio of low and high frequency component of heart rate variability, associated with sympathetic branch of autonomic nervous system was higher at night than in the morning and after positional changes. LF/HF ratio decreased in the week with more physical activity. Relevant information on determinants of microcirculation changes can be obtained using multimodal sensing supported by small devices that measure individual and environmental parameters.