Measurement for Quantum - M4Q
Measurement for Quantum - M4Q
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Researchers use microwave to measure human hydration

Researchers developing wearable device

  • New method developed to measure hydration using microwaves
  • Plans to develop wearable device that could be used in healthcare, by athletes and animals.

Scientists at NPL, working in collaboration with Queen Mary University of London have successfully developed a method using microwaves to measure blood-based molecules associated with dehydration.

Current methods of measuring levels of hydration can be time-consuming, involving multiple blood or urine tests, but critically are not real-time. Using data from the research is key to the next stage of development of a wearable device that can be used for medical purposes or by athletes to monitor hydration in real time. The device will also be able to be used for measuring hydration levels in pets and farm animals.

The use of microwaves for the measurement of human hydration has been demonstrated previously, but this NPL and Queen Mary work is the first metrology grade investigation into the relationship. The scientists have utilised a NPL traceable microwave capability to examine changes to red blood cells, proteins and salts, linked to dehydration. They found they were able to accurately measure the levels of these biomarkers in different solutions using dielectric sensors that recorded how much of the microwaves were absorbed when passed through the samples. 

This research builds on previous work from NPL’s Dr Richard Dudley and Dr Mira Naftaly, who developed a wearable device called Hydration Sensor, which uses microwaves to monitor hydration by measuring water levels in the body.

Dr Richard Dudley, Science Area Leader at NPL said: “The development of our on-body hydration monitoring device has been held back by two challenges.

  1. A quantifiable relationship between blood and microwave measurements.
  2. A measurement device that is easily contacted to a subject that remains stable for at least an hour.

Working with Queen Mary has helped us address the first and we are now confidently working towards engineering a solution for the second. Our ambition is to see our ‘hydration devices’ sold alongside heart rate monitors and blood pressure systems.”

The team from NPL and Queen Mary, will use the Hydration Sensor technology from NPL, which attaches via the ear lobe, to transform the microwave sensor system into a simple, portable device that can track selected biomarkers of dehydration over time.

Dr Tina Chowdhury, Senior Lecturer in Regenerative Medicine at Queen Mary University of London, said: “The next step for us is to turn the microwave sensor into a non-invasive, wearable device that could be used to track the biomarkers associated with dehydration in real time. We hope these devices could provide a portable and reliable way for athletes to detect dehydration in future, so we will need to investigate the suitability our current prototype device to ensure it works for athletes during moderate to strenuous exercise.

“However the applications of this technology aren’t just limited to the sporting community. The ability to track important molecules and proteins in human blood, which are well-known signs of dehydration, is also of importance for healthcare settings.”

Dr Rob Donnan, Reader in Terahertz Engineering at Queen Mary University of London, said: “Adapting conventional microwave instrumentation to biological study requires careful thought for meaningful data to be obtained. This work has begun to do this and we look forward to developments that may lead to a viable patch sensor for gauging how hydrated a person is.”

The research was funded by the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation and contributes towards continuing work to support their Healthcare Technologies Theme.

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