In recent years, with the increasing number of extremely hot days, concerns about health hazards caused by heatstroke have grown across society.
The importance of heatstroke prevention and proper hydration management is drawing increased attention in various fields, including sports, healthcare, and industrial workplaces.

However, conventional methods for measuring sweat rates face challenges such as large and expensive equipment and the difficulty of real-time monitoring. To address these issues, a research team at the University of Southern California has developed a new wearable sweat rate sensor (SR sensor), aiming to make it accessible and easy to use for everyone. This SR sensor is attracting significant attention as a groundbreaking technology that enables continuous and highly accurate monitoring of sweat volume.

In experiments conducted to thoroughly evaluate the performance of this innovative SR sensor, Takasago Electric’s electroosmotic flow pump IBP Series played a crucial role.

Reference: Islam, M. S. et al., Printed Wearable Sweat Rate Sensor for Continuous In Situ Perspiration Measurement. Advanced Intelligent Systems, 2024.

Challenge and Solution

The newly developed SR sensor is compact, lightweight, wearable, and designed to be disposable. To evaluate the sensor’s sensitivity, accuracy, and responsiveness, Takasago Electric’s electroosmotic flow pump IBP Series, known for its stable micro-flow delivery and high reproducibility, was used to flow artificial sweat through the sensor.

Reference: Islam, M. S. et al., A Wearable Sweat Rate Sensor with Adaptive Sweat Ion Concentration Calibration. IEEE Sensors Letters, 2025.

Human skin contains approximately 150 sweat glands per square centimeter, and each gland is known to produce sweat at a rate of 1 to 20 nL/min. Assuming that the sensor’s sweat inlet with a diameter of 4.5 mm is in direct contact with the skin surface, the theoretical maximum sweat collection rate is estimated to be approximately 1.8 μL/min.
To simulate this minute amount of sweat and evaluate the sensor’s measurement accuracy, a fluid delivery system with precise flow control was essential.

As a result of the verification experiments, it was confirmed that the sensor can detect sweat rate changes with extremely high sensitivity of 0.01 μL/min. This high-precision measurement was made possible by the stable microflow control performance of Takasago’s indirect-drive electroosmotic flow pump IBP Series.
The research results were published in the academic journal Advanced Intelligent Systems by Wiley. The SR sensor is expected to significantly advance personal health monitoring technologies and contribute to the expansion of healthcare applications in the future.

* Electroosmotic Flow Pump (Indirect Drive Type) – IBP Series

This is an indirect-drive pump that uses an electroosmotic flow pump (EOP) as a pressure source. By using the EOP to drive an intermediate fluid, a diaphragm is compressed, and the transport liquid is discharged.
In the experiment, deionized water was used as the intermediate fluid, and artificial sweat was delivered as the target fluid.