Three young girls 20s wearing colorful striped pyjamas

‘Smart’ pyjamas give new insights into sleep patterns

Image credit: Vadymvdrobot | Dreamstime.com

Researchers from the University of Massachusetts at Amherst have developed pyjamas embedded with self-powered sensors that provide unobtrusive and continuous monitoring of heartbeat, breathing and sleep posture – a ‘smart’ garment that could help improve sleeping patterns.

Known as the ‘Phyjama’, the shirt can be used to monitor the wearer’s sleep quality, such as the amount of REM sleep they are getting, which occurs at intervals during the night and is characterised by rapid eye movements, dreaming and bodily movement, or if they have breathing issues during the night.

Five lightweight sensors are sewn into the lining of the shirt. Four of these detect constant pressure, like that of a body pressed against a bed. The fifth, positioned over the chest, senses rapid pressure changes, providing information about heart rate and breathing.

The sensors are connected by wires made from thread thinly coated in silver. “They are sewed onto the seams of the shirt, so you don’t see them,” said Dr Trisha Andrew, director of the Wearable Electronics Lab at UMass Amherst.

Signals collected from the five patches are sent to a tiny circuit board that looks and functions like an ordinary pyjama button. The button has a built-in Bluetooth transmitter that sends the data wirelessly to a computer for analysis.

The sensors are connected by wires made from thread thinly coated in silver so they are completely undetectable for the wearer

Image credit: Trisha L Andrew/SWNS.COM

“Smart apparel with embedded self-powered sensors can revolutionise human behaviour monitoring by leveraging everyday clothing as the sensing substrate,” Andrew said.

“Our smart pyjamas overcame numerous technical challenges,” she added. “We had to inconspicuously integrate sensing elements and portable power sources into everyday garments, while maintaining the weight, feel, comfort, function and ruggedness of familiar clothes and fabrics.

“We also worked with computer scientists and electrical engineers to process the myriad signals coming from the sensors so that we had clear and easy-to-understand information.”

According to the US National Institutes of Health, getting enough sleep can help protect people against stress, infections and multiple diseases, such as heart and kidney disease, high blood pressure and diabetes.

Previous studies have found that quality of sleep also increases mental acuity and sharpens decision-making skills. However, most people don’t get enough sleep, or the right kind.

Some manufacturers of smart mattresses claim the products can sense movement and infer sleep posture. However, these mattresses do not provide detailed information of the sleeper and are not portable for travel.

To overcome this, commercially available electronic bands, such as a Fitbit or an Apple Watch, worn on the wrist give information about heart rate and monitor how much total sleep the wearer gets.

The UMass Amherst team, however, are developing their own solutions.

“We use reactive vapour coating to transform commonly-available, mass-produced fabrics, threads or premade garments into a plethora of comfortably-wearable electronic devices,” Dr Andrew explained.

Signals collected from the five patches are sent to a tiny circuit board that looks and functions like an ordinary button

Image credit: Trisha L Andrew

These first-of-their-kind patches are used in different parts of the pyjamas, so that the researcher scan determine sleep posture. Also, the patches detect quick changes in pressure, such as the physical pumping of the heart, which provides information on heart rate, being the first time such a sensor has been shown to detect tiny signals from the heart.

The pyjama shirt is still in its early stages and has been tested overnight on only eight people. Furthermore, the team is still in the process of ensuring the sensors are accurate for a variety of body shapes and heights.

Andrew says the shirt cannot yet be used to diagnose medical issues, but the goal is to eventually replace lab-based sleep studies where participants are hooked up to various machines overnight, using the pyjama as an alternative for testing.

The technology is being expanded to wearable electronic sensors that detect gait and send feedback to a monitor to help prevent falls in residents living in care homes and sheltered accommodation.

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