When Does a Fitness Tracker Become a Medical Device?

Smartwatches, fitness trackers and wearable devices may be capable of estimating blood pressure, monitoring blood oxygen levels, tracking heart beats, and even detecting changes in temperature and activity levels that can signal an impending illness. Not long ago, these measurements were primarily collected in doctors’ offices, hospitals, and specialized clinics, but today users can review these metrics with a simple touch of a button.

These technologies hold tremendous promise. By continuously collecting physiological data, wearables could help identify early signs of disease, track recovery from illness and provide a more complete picture of a person’s health over time. But as these devices become increasingly sophisticated—and increasingly intertwined with healthcare—an important question remains: How can consumers and clinicians know whether the information they provide is accurate enough to guide health decisions?

That question became more urgent in January 2026 when the U.S. Food and Drug Administration (FDA) released updated guidance for “low-risk” wellness products. Under the policy, some noninvasive devices that estimate physiological measurements, including blood pressure and blood oxygen levels, may qualify as general wellness products rather than regulated medical devices. As long as manufacturers market these features for “wellness purposes”, they may not be subject to the same regulatory requirements as traditional medical technologies.

The change was intended to promote innovation and reduce unnecessary regulatory burden. But as consumer wearables continue to evolve from fitness trackers into tools that generate clinically relevant information, the distinction between wellness products and medical devices is becoming increasingly difficult to define.

For Jessilyn Dunn, the Theodore Kennedy Associate Professor of biomedical engineering and biostatistics & bioinformatics at Duke University, that ambiguity raises important concerns.

Dunn directs the BIG IDEAs Lab (Biomedical Informatics Group: Integrating Data Engineering and Analytics), where researchers develop methods to use wearable-device data and digital biomarkers to better understand human health. The team’s work explores how physiological signals collected outside of traditional healthcare settings can help identify everything from acute infections such as COVID-19 and influenza to chronic conditions including heart disease and diabetes.

“Before this policy change, for devices that output clinically relevant parameters, the manufacturers were required to work with the FDA to demonstrate validity of the measurements,” said Dunn. “But as regulatory oversight recedes, these responsibilities are increasingly assumed by consumers and clinicians.”

“Disclaimers don’t change the reality that people use wearable data to guide medical decisions,” she said. “Poorly validated devices can increase clinician workload, jeopardize patient safety, and weaken trust in the technology.”

In a commentary published June 23 in Nature Biomedical Engineering, Dunn and her colleagues examined the FDA’s updated guidance and identified several areas where they believe additional clarity is needed.

One of their primary concerns is that the guidance allows manufacturers to describe device outputs as “validated” without specifying what validation should entail. The policy does not establish minimum requirements for study design, sample size, population diversity, independent testing, or public reporting of results.

As a result, the researchers argue, products may present measurements that resemble clinical data without meeting the evidentiary standards typically expected of medical devices.

The issue becomes increasingly important as wearable companies seek deeper integration with healthcare systems. Companies such as Oura and WHOOP have introduced services that allow users to share wearable-generated health information with healthcare providers and, in some cases, connect directly with physicians through telehealth platforms. In June 2026, the Food and Drug Administration also allowed WHOOP to market its Blood Pressure Insights feature as a wellness tool, reversing their 2025 warning that the tool was a medical device that required review.

“Anecdotal evidence suggests that abnormal readings from consumer wearables are often confirmed using FDA-cleared devices, but ‘normal’ readings may be accepted without additional testing,” said Dunn. “A falsely normal result may reassure a user that no action is needed, potentially delaying diagnosis or treatment.”

Blood pressure measurements illustrate the challenge. Inaccurate readings could either delay treatment for hypertension or lead to unnecessary anxiety, clinical visits, and medical testing. Even the way information is presented—through numerical displays, trend graphs, alerts or color-coded indicators—can influence how users interpret the data, regardless of whether the manufacturer explicitly markets the feature as medical.

Despite these concerns, Dunn emphasizes that the long-term potential of wearable technologies remains enormous.

“We’re not questioning the value of wearable technology; we’re working to ensure it reaches its full potential,” she said. “When wearable data is rigorously validated and thoughtfully integrated with clinical care, it can help detect disease earlier, support more personalized treatment, and improve health outcomes.”

To help realize that vision, Dunn and her colleagues recommend establishing minimum validation standards for wellness devices that generate clinically relevant measurements, addressing informational risks associated with inaccurate data, clarifying the distinction between wellness and medical products, and requiring greater transparency about device performance and regulatory status. They also suggest that wellness products clearly disclose when their measurements have not been evaluated, cleared or approved by the FDA.

Without those safeguards, the researchers warn, the FDA’s updated guidance could unintentionally create a two-tier digital health ecosystem in which consumers receive increasingly medical-looking information without the protections traditionally associated with clinical tools.

“These devices can generate an unprecedented amount of data that could eventually help identify disease earlier, personalize treatments and improve preventive care,” said Dunn. “When these tools are validated appropriately, they can expand access to healthcare and support preventative medicine. Strengthening transparency, validation standards and regulatory clarity would help ensure that innovation advances alongside safety.”