Scientists in Canada have created a smart T-shirt that monitors the wearer’s respiratory rate in real time.
This innovation paves the way for manufacturing clothing that could be used to diagnose respiratory illnesses or monitor people suffering from asthma, sleep apnea, or chronic obstructive pulmonary disease. The research is published in Sensors.
The innovation has come from Université Laval’s faculty of science and engineering and its Centre for Optics, Photonics, and Lasers.
Unlike other methods of measuring respiratory rate, the smart T-shirt works without any wires, electrodes, or sensors attached to the user’s body, explains Prof Younès Messaddeq, who led the team that developed the technology.
“The T-shirt is really comfortable and doesn’t inhibit the subject’s natural movements. Our tests show that the data captured by the shirt is reliable, whether the user is lying down, sitting, standing, or moving around,” Messaddeq says.
The key to the smart T-shirt is an antenna sewn in at chest level that’s made of a hollow optical fibre coated with a thin layer of silver on its inner surface. The fibre’s exterior surface is covered in a polymer that protects it against the environment.
“The antenna does double duty, sensing and transmitting the signals created by respiratory movements. The data can be sent to the user’s smartphone or a nearby computer,” adds Messaddeq, who also holds the Canada Excellence Research Chair in Photonic Innovations.
As the wearer breathes in, the smart fibre senses the increase in both thorax circumference and the volume of air in the lungs, explains Messaddeq. “These changes modify some of the resonant frequency of the antenna. That’s why the T-shirt doesn’t need to be tight or in direct contact with the wearer’s skin. The oscillations that occur with each breath are enough for the fibre to sense the user’s respiratory rate.”
To assess the durability of their invention, the researchers put a T-shirt equipped with an antenna through the wash. “After 20 washes, the antenna had withstood the water and detergent and was still in good working condition,” says Messaddeq.
In addition to Messaddeq, the study’s coauthors are Philippe Guay, Stepan Gorgutsa, and Sophie LaRochelle. (SV