Millions of Americans now head out the door each day wearing devices that count their steps, check their heart rates, and help them stay fit in general. But with further research, these “wearables” could also play an important role in the early detection of serious medical conditions. In partnership with health-care professionals, people may well use the next generation of wearables to monitor vital signs, blood oxygen levels, and a wide variety of other measures of personal health, allowing them to see in real time when something isn’t normal and, if unusual enough, to have it checked out right away.
In the latest issue of the journal PLoS Biology , an NIH-supported study offers an exciting glimpse of this future. Wearing a commercially available smartwatch over many months, more than 40 adults produced a continuous daily stream of accurate personal health data that researchers could access and monitor. When combined with standard laboratory blood tests, these data—totaling more than 250,000 bodily measurements a day per person—can detect early infections through changes in heart rate.
The study, led by Michael Snyder, a scientist at Stanford University, Palo Alto, CA, grew out of a larger ongoing clinical research study that tracks adults who are healthy or pre-diabetic for genomic and biochemical clues into health and disease. The researchers wondered whether adding wearables to the study could give them another window into the differences between early diabetes and health.
After evaluating more than 400 wearables, the team members settled on seven that were inexpensive and easy to use. With the participant’s consent, manufacturers were willing to provide access for researchers to the health data. The wearables included MOVES, an activity and positional tracker; Basis smartwatches, which measure everything from steps to sleep; and iHealth Finger for blood oxygen levels. The other devices were a Masimo Pulse Ox, RadTarge, Scanadu Scout, and a Withings scale.
The next step was to perform a trial run that rigorously evaluated the wearables and their capabilities. For that, they turned to Snyder himself. For most of the next two years, he wore the seven selected wearables strapped to his wrist, belt, shirt, and finger. They continuously measured his steps, physical activity, calories, heart rate, skin temperature, sleep, blood oxygen, exposure to radiation, and weight. The data streamed in real time to his smartphone for immediate access. In addition, Snyder frequently received standard medical tests at Stanford to provide a point of comparison for his wearable data.
The results were quite impressive. Because Snyder flies frequently, he noticed his blood oxygen levels dropped during high-altitude flights, and that correlated with a sense of fatigue. Snyder looked in the medical literature and found that this phenomenon wasn’t well documented. So he and later 17 other study participants have used their wearables to provide continuous measurements of their low blood oxygen levels during flights. Snyder doesn’t know whether the drop during flights should be a problem for most healthy people, but it might be a concern for those with chronic conditions or poor circulation. Thanks to the constant health monitoring, he now has the data if anyone would like to take a closer look.
In one instance, the wearables also helped Snyder avoid coming down with a serious illness. After visiting his brother in an area of Massachusetts known for a high rate of the a potentially debilitating tick-borne Lyme disease, Snyder was aboard a flight to Norway when he noticed his heart rate was elevated and his blood oxygen was lower than expected, even for a plane flight. Snyder recognized this as a possible indication of infection and knew that he needed to have it checked out, especially since he and his wife were planning to depart soon on a cruise that would wend its way above the Arctic Circle.
After landing in Oslo, Snyder visited a doctor, who confirmed with a blood test that his immune system was reacting to something. The doctor, unfamiliar with Lyme disease, proposed a prescription of penicillin. Snyder insisted on oral doxycycline, the standard treatment for Lyme disease.
Within a day of taking doxycycline, Snyder saw that his heart rate and skin temperature returned to normal. When Snyder returned home feeling well, he received a standard blood test for Lyme disease. The results were positive. He had been bitten by a tick in Massachusetts.
Now satisfied the wearables were highly accurate in their measurements, Snyder and his research team asked 43 adults enrolled in the larger study to wear a Basis smartwatch for up to 11 months. It measured calories, heart rate, steps, sleep, skin temperature, and galvanic stress response (electrical conductance of your skin). With such a heavy flow of data, the researchers found that people really do have their own unique Circadian rhythm, confirming that medicine must continue to evolve to treat the person, not the generic patient.
They also confirmed that other participants have an elevated heart rate and skin temperature above their normal baseline when they become ill. In fact, the team has developed an algorithm to identify periods when people first become ill.
Snyder warns that no FDA-approved medical apps are currently available for common wearables, such as smartwatches. While it’s certainly possible to use them now to monitor many things, as this study shows, more research is definitely needed.
And that opportunity is about to expand in a big way. The Precision Medicine Initiative® All of Us Research Program, which is set for launch later this year, will aim to enroll a million Americans in a prospective study of health. Many of those participants will be offered the opportunity to use wearables that will provide real time measurements of their health and environmental exposures, greatly expanding this type of research. Until then, reports like this one offer hope. They remind us that we’re getting closer to a new data-driven era when your smartphone could be your dashboard for everyday health maintenance.
 Digital Health: Tracking physiomes and activity using wearable biosensors reveals useful health-related information. Li X, Dunn J, Salins D, Zhou G, Zhou W, Schüssler-Fiorenza Rose SM, Perelman D, Colbert E, Runge R, Rego S, Sonecha R, Datta S, McLaughlin T, Snyder MP. PLoS Biol. 2017 Jan 12; 15(1): e2001402.
Michael Snyder Lab (Stanford University, Palo Alto, CA)
Video: Michael Snyder (Stanford School of Medicine)
NIH Support: National Institute of Biomedical Imaging and Bioengineering; National Center for Advancing Translational Sciences; National Institute of Diabetes and Digestive and Kidney Diseases