Since the first Apple Watch release in 2015, wearable technology has become a lucrative and rapidly growing industry, worth over $34 billion dollars in 2020. These products soon included companies like Garmin and Fitbit offering “smart” wearables geared towards tracking fitness-related metrics, such as step count, calories burned and heart rate. Now, endless iterations of wearable technology exist, which claim to extract information about various biological behaviours, morphing into a scientific domain in and of itself. Current measurable biosignals include heart rate and heart rate variability, skin conductance and temperature – generally pointing towards complete user-driven monitoring of 24/7 human performance. This offers an unprecedented window into human health.
Further, this technology is now branching out to the clinical field. Many physicians support devices to enhance patient care – user-directed devices that keep a watchful record of patient activity outside of strict clinical observations. Whether you’re an endurance athlete training for an IRONMAN, a person looking to get text messages on their wrist along with a step count, or a physician, there’s a wearable product out there for you. The implications for wearable technology are monstrous, but the question remains – how reliable are these products, and should we be using them to guide our daily lives, or further, medical care?
A study conducted in 2018 by the Heart Rhythm Society of America tested the accuracy of wearables measuring baseline heart rate and rapid heart rate and found that the brands tested (Apple, Fitbit, and Samsung) were almost 100 percent accurate for these metrics. A professor from the University of Wisconsin cited that intended use for these wearables dictates the accuracy – most are accurate enough for most people and purposes. Still, it ultimately depends on the intended measurement. Most people have no reason, other than curiosity, to know their caloric burn or heart rate variability throughout the day and should not be using the information their watch gives them to adjust their diet or activity. For the most part, wearables can accurately measure step count, with few exceptions. At rest, the heart rate measured by these devices tends to be accurate but less so during the activity itself. These trackers cannot know certain things about one’s body, so the assumptions made on behalf of the wearable technology are often off when it comes to more vigorous activity. Caloric burn is hard to estimate outside of wearable tech, never mind within, so this is considered an inaccurate metric when measured by such a device.
These devices generate monstrous amounts of low-cost data throughout the day. As the intended measures and usage of the data become more complicated, the accuracy of said device decreases. Our biological systems’ unpredictable and interdependent nature across different states of “health” as humans presents a real challenge to measurement accuracy. The popularity and advancement of artificial intelligence may help personalize these now standardized devices to individual systems to a certain extent. Still, there is a question as to whether it will ever be sufficient to guide clinical decisions.
As of now, there is little evidence to support the widespread use of wearables in clinical practice. However, numerous tech start-up companies around the globe are dedicated to developing technology to enhance wearable health device accuracy and integrate the data these devices collect into electronic health records. Various insurance companies are now encouraging the growth and uptake of wearables through health tracking and incentive programs for their customers. These companies claim to continue analyzing best practices and potential solutions to mitigate existing challenges to complete integration of these devices into the healthcare system. There is potential to integrate wearable technology with surgical operations, improve stroke rehabilitation, sharpen clinical diagnoses and guide treatment. The emerging scientific domain of wearable technology has many exciting possibilities, but it isn’t significant without accuracy and proof! So, for now, your smartwatch is probably best used for checking time and texts on the go.