Pajamas that monitor our health while we sleep

Presented at the Ubicomp 2019 conference, this intelligent sleepwear is able to analyze different vital functions of our body, such as heart rate and breathing rate. A valuable help for elderly patients with sleep disorders.

Pajamas that can record in real time and analyze our physical and physiological constants while we sleep: this is what the inventors of the "Phyjama", the first intelligent pajama, promise.

As connected clothing promises to be the future of life monitoring and personalization of health care, researchers at the University of Massachusetts Amherst have just developed the first intelligent sleepwear.

Made in a textile capable of detecting physiological functions, this "Phyjama" was presented at the Ubicomp 2019 conference held this week in London. It is also the subject of a study published in Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (IMWUT).

A technology based on the pressure of the textile on the body

To develop these pajamas 2.0., the two students behind the project and their teachers had to ask themselves the right questions. Among these: how to create a connected sleepwear that stays loose and is comfortable to wear?

"The challenge we faced was to obtain useful signals without changing the aesthetics or feel of the textile," explains Professor Trisha L. Andrew, materials chemist. In general, people assume that intelligent textiles refer to very tight clothing with various sensors integrated to measure physiological and physical signals, but this is clearly not a solution for everyday clothing and, in particular, sleepwear.

However, the researchers found that even when worn loosely, the Phyjama's fabric was pressed against the body during sleep. "This includes the pressure exerted by the torso against a chair or bed, the pressure when the arm rests on the side of the body during sleep, and the slight pressure of a blanket on sleepwear," says the materials chemist Deepak Ganesan, who co-supervised the work.

"These areas under textile pressure are potential locations where ballistic movements caused by heartbeat and breathing can be measured," he continues,"and these can be used to extract physiological variables. The difficulty is that these signals may be individually unreliable, especially in loose clothing, but the signals from many sensors placed on different parts of the body can be intelligently combined to obtain a more accurate composite reading."

A valuable tool for older people

At the conference, the researchers explained that they realized that there was no tissue-based method to detect continuous and dynamic changes in pressure, especially on the small signals they needed to measure. So they designed a new fabric-based pressure sensor and combined it with a triboelectric sensor - a sensor activated by a change in physical contact - to develop a set of distributed sensors that could be integrated into loose clothing such as pajamas.

This combination allowed them to detect physiological signals in many different postures: the heartbeats were detected with great precision, as well as the breathing rate.

According to them, this Phyjama could become a valuable tool for measuring sleep quality and analyzing vital functions. "We expect these advances to be particularly useful for the follow-up of elderly patients, many of whom suffer from sleep disorders," says Prof. Andrew,"Current generation clothing, such as smart watches, is not ideal for this population, as seniors often forget to wear them regularly or resist wearing additional devices, while sleepwear is already an integral part of their daily lives. In addition, your watch cannot tell you in which position you are sleeping and if your sleeping position affects your quality of sleep. Our Phyjama can."