Place your finger on the screen: the smartphone determines dehydration level

In today's world, where smartphones are involved in almost every aspect of human life, their capabilities are expanding in another direction. Scientists at King Abdullah University of Science and Technology in Saudi Arabia have developed a method to determine the body's hydration level — that is, water content — using a regular smartphone.

The scientists have proven that it is possible to obtain information about the body's water balance by using capacitive sensors already present in modern smartphones. It turns out that these sensors are capable not only of detecting the finger’s charge but also of measuring the skin’s dielectric transition capability — that is, its ability to store charge. This indicator significantly decreases when the body is dehydrated.

A research team led by Professor Tariq Al-Nafouri developed a special machine learning algorithm based on changes in the dielectric properties of the skin. This algorithm can classify a person's hydration state into five main categories. A total of 45 people participated in the experiment: 35 were fasting during Ramadan, and 10 were athletes engaged in training of varying intensity.

The testing process is very simple: the participant simply places a finger on a special sensor — a smartphone screen simulator — and enters information about their gender and weight. Based on this data, the system makes an almost accurate conclusion about the amount of water in the body. According to the results, the technology worked with 87% accuracy in fasting individuals and 92% accuracy in athletes.

One of the project’s authors, Sumia Suyousef, stated that in the future this function could be directly integrated into a mobile app. Thus, every user will have the ability to constantly monitor their body's fluid balance using their smartphone.

This innovative achievement is expected to become a useful everyday function not only for athletes but for anyone concerned about their health. Since dehydration is one of the main causes of many health problems, this invention could become an important step at the intersection of medicine and mobile technology.