IoT Wrist Sensor Taps into Sweat to Gather Health Data

Population health management is a hotspot where data collected from IoT sensors has the potential to bring broad rewards.

Photo: Stanford Medicine News Center

With a bevy of IoT-based fitness and certified medical devices coming to market, data streams from wearables and health monitoring devices can be used alongside clinical data to provide doctors with a clear, near real-time picture of a patient’s health.

Wearable IoT devices play an integral role in automatically gathering patient data. So much so that the global wearable medical devices market has been valued at $23 million and is expected to expand at a 6.9% CAGR over the next 10 years, according to Future Market Insights. Solution providers will be tasked with the critical role of collecting vitals—working with hospitals, physicians and medical device manufacturers to gather and process data collected from these millions of health wearables.

Smart Sensors to Fight Expensive Problems

Diabetes management is one of the more expensive healthcare challenges for patients, doctors and healthcare networks. About 347 million people worldwide have diabetes, according to the World Health Organization, and the cost of treating diabetes is estimated to be $500 billion worldwide. Another disease with a similar degree of difficulty to diagnose and treat is cystic fibrosis, a genetic disease that occurs in one in every 2,500 white newborns in the United States.

Stanford researchers have developed a wearable that will help with the treatment of each of these conditions. They have built a wrist-ready prototype that generates a few drops of perspiration, just enough for its IoT sensors to measure blood sugar and to automatically monitor other bodily functions.

One of the goals for the device was to show that it is possible for people to wear lightweight devices that can deliver on the promise of pain-free diagnosis. “You don’t have to stick people with anything. You can wrap it on people’s hands and have them engage in their daily activities and continuously monitor them,” says developer Sam Emaminejad, in an interview with NBC News.

Blood vs. Sweat and Tears

Emaminejad, who helped build the device while at Stanford and is now an assistant professor at UCLA, notes that what a wearable health device needs is enough bodily fluid (whether blood, sweat or tears) to measure something, such as blood sugar, sodium or hormones.

For diabetes, the typical method for measuring blood glucose is using a needle to extract blood samples. Conventional methods for diagnosing cystic fibrosis require that patients visit a specialized center and sit still for up to 30 minutes, while electrodes stimulate sweat glands in their skin to provide sweat for the test. Patients then have to wait while a lab measures the chloride ions in the sweat to determine if the patient has cystic fibrosis.

The Stanford wearable works much faster to grab data, using sweat-stimulating compounds and a low current. It can measure glucose, sodium and other compounds and wirelessly relays data. The platform extracts sweat at a high secretion rate on demand or periodically performs sweat analysis in place.

Here’s how it works. The two-part system of flexible sensors and microprocessors sticks to the skin, stimulates the sweat glands and then detects the presence of different molecules and ions, based on their electrical signals. The more chloride in the sweat, for example, the more electrical voltage is generated at the sensor’s surface. The team used the wearable sweat sensor in separate studies to detect chloride ion levels—high levels are an indicator of cystic fibrosis—and to compare levels of glucose in sweat to that in blood. High blood glucose levels can indicate diabetes.

One Problem, Multiple Solutions

Many other groups are working to develop wearable health tech, including the glucose-sensing contact lens being tested from Google. The contact lens contains an embedded wireless chip and a miniaturized glucose sensor and antenna that can rapidly measure blood sugar levels for people with diabetes.

IoT wearable Diabetologia

Photo: Diabetologia

Another system currently in testing is the “artificial pancreas,” which is really a series of linked devices that monitor blood sugar and deliver insulin as needed for diabetes patients. Developed by Boston University/Massachusetts General Hospital, the artificial pancreas system uses a smartphone to help control a diabetic's blood sugar monitoring and insulin delivery. The system includes a wearable blood glucose monitor, a wearable insulin pump and a smartphone controller. The devices communicate wirelessly through Bluetooth technology.

While each of these solutions attacks disease management from different angles, they all rely on advancements in IoT wearables. Healthcare providers, along with solution providers who can deliver and analyze data for clinicians, have unprecedented opportunities to improve patient outcomes and significantly reduce the costs of managing chronic conditions.

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