Low-cost wearable non-invasive sensor coupled with Arduino Uno system to monitor hydration status during physical activity

Abstract

Dehydration is a common health challenge among athletes. Many attempts have been made to detect dehydration using the conductivity of perspiration as a biomarker. However, due to the poor reliability and portability of those devices, the requirement for an alternative detection method is required. Thus, a real-time human sweat conductivity-based portable non-invasive device combined with an interdigitated electrode sensor (IDE and DS18B20 sensor) and an Arduino Uno platform was developed. Sweat impedance was used to predict hydration status. An Android application was designed to provide alerts via Bluetooth connection to alarm the user regarding the hydration status. The device was calibrated with a 10 μS KCl solution and cross-checked with the conductivity of known electrolytes. The sensor was tested for human sweat before and after consuming commercial electrolyte beverages in a controlled exercise environment. Results showed a noticeable 2.42 (± 0.26) times average conductivity increase compared to the initial conductivity with a 10.61% percentage deviation for each person before reaching a predefined dehydration level without consuming any electrolyte. After electrolyte consumption, this value was reduced to 2.03 (± 0.44) with a higher percentage deviation of 21.72%. Initial average conductivity and the increase in percentage sweat conductivity were used to programme the device to provide a warning signal to the user regarding potential dehydration.