Wearable Photoplethysmography for Dehydration

The trial aims to determine if a wearable device can measure hydration by analyzing blood flow just under the skin. Instead of traditional methods like checking body mass or urine, the study uses light sensors on the device to detect changes in blood volume, which might indicate hydration levels. Participants will be divided into two groups: one will stay hydrated, and the other will limit fluids to test the device's accuracy. Those who frequently exercise and are willing to wear a wrist device while following specific guidelines, such as fasting overnight, may be suitable for this study. As an unphased trial, this study offers a unique opportunity to contribute to innovative research that could revolutionize hydration monitoring.

The trial does not specify if you must stop taking your current medications, but it mentions that you cannot take medications that might interfere with the study. It's best to discuss your current medications with the study team to see if they are allowed.

Research has shown that wearable devices using light sensors, known as PPG, are generally easy for people to use. In a study with 240 participants, researchers tested a wearable hydration sensor using PPG and other technologies. They carefully monitored participants to ensure they did not lose too much water, emphasizing a focus on safety. The study reported no serious side effects, indicating these devices are safe for everyday use.

Researchers are excited about wearable photoplethysmography for dehydration because it offers a non-invasive way to monitor hydration levels in real-time, unlike traditional methods that rely on blood tests or urine analysis. This technology uses light to measure changes in blood volume under the skin, providing immediate feedback. This could revolutionize how dehydration is detected and managed, especially in athletes or individuals in demanding environments, by offering continuous, on-the-go monitoring without the need for lab tests.

This trial will compare the effectiveness of wearable photoplethysmography (PPG) in monitoring hydration levels between two groups: the Euhydrated Group, where water compensates for sweat loss during exercise, and the Dehydrated Group, where fluid is restricted. Research has shown that wearable devices can monitor hydration using PPG technology, which shines light through the skin to assess blood flow and indicate hydration levels. In a study with 240 participants, these devices accurately tracked hydration changes using PPG and other sensors. Another study found that combining PPG with machine learning enhanced hydration monitoring. Although no wrist-worn device can perfectly predict hydration yet, early results for this method are promising.¹³⁵⁶⁷