Your heart on your sleeve
Everyday clothes with invisible sensors woven in can monitor your vital signs. Future designs could tell you – or your doctor – when something is amiss
New Scientist, 3 April 2014
HEY smarty pants. Your underwear could soon tell if you are falling ill before you know it yourself, notify others if you've fallen over or help doctors diagnose and treat diseases.
Clip-on sensors or wristbands can already monitor a wearer's vital signs, such as activity levels and sleep patterns. But the rigid form of these devices limits what signals they can pick up and they won't work if you forget to wear them.
The next generation of wearable technology aims to embed sensors in your clothes, so you only need to get dressed to start monitoring your health."Wearable electronics are great but the only way they are going to take off is if you stick them on something people have to wear every day," says Simon McMaster of Footfalls and Heartbeats, a company in New Zealand that is developing smart fibres with sensors knitted straight into the fabrics.
With conductive or optical sensors woven into T-shirts, shorts and underwear, smart clothes will be able to pick up a greater range of body signals, at much higher sensitivities, than rigid sensors.
"You can put the sensor wherever you want," says McMaster. "Using conductive yarn you can control the structure and the conductivity in that area and make it more or less conductive, measure compressive force, tensile force, temperature," he says.
Wearable sensors will have to be invisible if they are to be adopted widely, says Mark Pedley of wearable tech company SmartLife in Leicester, UK. "The future has got to be something that's discreet or invisible, so they can put the thing on, relax, and it will work."
Like Footfalls and Heartbeats, SmartLife incorporates sensors in the fabric rather than using hard ones. "We can integrate them into the garment so they give maximum comfort, they are fully washable, and they are inexpensive to produce en masse," he says.
What can these clothes tell you? So far, early prototypes can measure heart rate through ECG sensors on a T-shirt or EEG sensors in a beanie hat can monitor brain activity. Tight clothes such as cycling shorts can also measure how hard muscles are working, and sensors on the chest can measure respiration rate, based on chest movements as the wearer breathes. They can also detect changes in body temperature and signs of stress such as sweating.
Wearable garments containing these sorts of sensors are already being used in niche medical situations. In 2010, researchers at the University of California developed smart underpants to monitor the vital signs of soldiers. And SmartLife has worked with several pharmaceutical companies to monitor the effects of drugs on people during clinical trials. "Instead of monitoring individuals for hours when they come into the trial, they can now monitor them in normal life and see how the drugs react," says Pedley. "The patients don't even know whether it's working or what the data is."
But as well as easily monitoring patients with a known condition, the real beauty of the technology will be in predicting health problems before they happen.
"Clothing is the universal medium," says Stephane Marceau, CEO ofOMsignal, a company based in Montreal, Canada, whose sensor-packed T-shirts are due to go on sale in a few months. "Wearable will go from looking at what happened to doing dynamic predictions and preventions – for example, predicting heart failure or seizures on a personal level, or predicting epidemics on a population level."
One obvious area is preventing heart conditions. The European Union is funding an international smart clothing research project called MyHeart, which it hopes will help prevent cardiovascular diseases – the leading cause of death in the West.
Meanwhile, Footfalls and Heartbeats is working with the University of Nottingham, UK, on smart socks that can predict the onset of diabetic foot ulcers. The socks are made from fibres that contain plastic optical fibres. The fibres shine a light on the skin to measure how well blood is pumping through the capillaries – sluggish flow can be a sign of ulcers. "If capillary refill is slow, an alert might say you need to take the weight off your feet or see a doctor," McMaster says. Measuring oxygen levels could also be a good way to detect health problems in older people.
OMsignal envisages a future where your vital signals could be sent to a doctor or a loved one. They'd be able to tell if you are getting too stressed, for instance, and send you a calming text message. Their T-shirts use thread-based sensors which are woven into the garment.
Products like this are not yet approved for healthcare by the US Food and Drug Administration, but those working in the field see this as the future of medicine.
For example, a company called Heapsylon in Redmond, Washington, already sells bras and T-shirts that contain heart rate sensors for use during exercise. But the same products might one day be able to predict stress, says Heapsylon CEO Davide Vigano. The company is also developing smart socks that can monitor speed, gait and balance in real time. Once they have enough data, they hope to develop predictive algorithms that could alert users that they are about to fall. Pyjamas embedded with sensors to detect breathing rate could also help people who suffer from sleep apnoea, triggering an alarm if breathing is interrupted.
More benign conditions could also be intercepted. Part of the allure of these wearable sensors is that they allow people to keep an eye on their own health. For instance, they could pick up small changes in temperature, sweating or coughing that suggest you have caught a virus, says Pedley. "There are clinical models that allow you to say: this is the onset of a virus and you need to take Lemsip today rather than in three days."
Data security will be key, cautions McMaster. As the technology develops, one issue that will need to be addressed is who gets to see the data. "You don't want an insurance company saying we won't touch you with a bargepole," he says.
The next step will be to incorporate chemical analysis, says Pedley. Those sensors might tell whether you are being exposed to too many chemicals or too much smoke in the environment and are at risk of an asthma attack, for instance, or could analyse the content of blood, sweat and tears – even urine. "I call it Star Trek stuff, but Star Trek isn't so far away," he says.