Wearable Health Devices and Personal Health Trackers: What You Need to Know

Jackie Liu, Emma Roy, and Diana Zuckerman, PhD, National Center for Health Research

Wearable electronic devices such as the FitBit or other SmartWatches are worn to track personal health data, such as how many steps you have taken in a day or your heart rate. About 30% of American adults use a wearable electronic device in 2022, and almost half of them use their device daily.1 This article will explain what wearable electronic health devices are, how they are used, when they are regulated by the FDA as medical devices, and the benefits and risks of using these devices.

How are wearable electronic devices used to track or improve your health?

Wearable electronic devices can be divided into two categories: personal use and clinical use. Personal use wearable devices are used by an individual to track their own health data, such as monitoring their heart rate during a workout or steps taken in a day. People tend to use these devices in order to improve fitness or lifestyle, not because of medical necessity. Clinical use wearable electronic health devices, such as blood sugar readers, are used by healthcare providers to monitor and better understand a patient’s health status. As technology advances, this distinction is becoming more and more blurred. 

Personal Use

Personal use wearable devices include fitness trackers such as Fitbit or the Samsung Galaxy Watch. There are also more specialized personal use wearable devices like the Ava wearable to track fertility. These devices collect health data from the wearer and send that data to the person’s smartphone to be stored and analyzed.

Fitness trackers can help people who want to improve their health through lifestyle changes. An example of such trackers are pedometers, which track the number of steps. Some research has found that pedometers help increase physical activity. For example, a 2007 review of 26 studies on pedometers used in an outpatient setting (rather than in the hospital) found that these devices increase daily physical activity by 27% over the participants’ initial step counts.2 A 2019 review of 35 studies of patients with chronic cardio-metabolic disease found that wearing a fitness tracker that counts steps helped people increase the number of steps they took per day by a median of 2,592 steps. Researchers in both studies concluded that since fitness trackers allowed users to track and quantify their physical activity, that encouraged wearers to lead a more active lifestyle.3 It should be noted that smartwatches with pedometer apps may encourage healthy habits, but are not always accurate. A 2017 study of college students using various brands of wearable electronic health devices with pedometer features were significantly underestimating the number of steps taken, with Fitbit being the least accurate.4 A 2020 review of the literature on consumer wearable health devices found that pedometers do not accurately measure step count, which can be a flaw in the device or due to user-error (such as placing the pedometer on the ankle instead of hip).5 

Clinical Use

Healthcare providers sometimes give wearable devices to patients with chronic diseases in order to monitor them or to assist them with everyday tasks. Examples of the wide variety of wearable electronic health devices include hearing aids, continuous glucose monitors for type 2 diabetes, and Holter Monitors for arrhythmia. In a 2016 study, researchers gave 400 patients a blood pressure cuff to monitor their blood pressure for 90 days.6 The data are collected in an app and sent to the healthcare provider’s office monthly so providers can respond to changes in patients’ blood pressure by altering medication dosages or other interventions. Patients also received monthly reports of their blood pressure measurements. Researchers found that 71% of participants using the cuff were able to achieve their target blood pressure. In comparison, only 31% of participants under usual hypertension care were able to achieve target blood pressure. Both the cuff and its app gave providers a better sense of a patient’s blood pressure over time, allowing them to more accurately adjust a patient’s hypertension treatment regimen. The app also gave patients immediate alerts if their blood pressure was too high as well as tips to lower their blood pressure, such as through diet and exercise. This, in turn, allowed patients to lower their blood pressure to a normal range.6 These are usually (but not always) considered medical devices, therefore they are regulated by the FDA.

Risk

While wearable electronic devices can enhance a person’s understanding of their body and a doctor’s understanding of their patient’s health, they also pose some risks. The combination of plastics and metals used to construct wearable devices can cause skin irritation and even chemical burns.5 Many consumers use these devices to track their health status by monitoring heart rate, blood pressure, and more. However, several experts have called the accuracy of these data into question. As noted earlier in this article, even simple products such as pedometers can be inaccurate, resulting in consumers making inappropriate health decisions based on seemingly sound information.

Some publications support getting the government involved in regulating health data. Staff at The Lancet and The Financial Times co-authored a report titled the Commission of Governing Health Futures.7 They urge countries to strengthen public safeguards on the use of digital health data because they are concerned that such information could be shared or sold to private companies without the knowledge of patients. This could result in sensitive patient data, such as medical condition, age, or weight, being given to corporations for them to profit off of, all without patient consent. By increasing government oversight on how health data is secured, experts hope that patients will not need to live in fear of their personal information being shared or sold unbeknownst to them.

There is also concern about the algorithms used in medical devices because they could be biased or inaccurate, resulting in discrimination in patient care.8 For example, a 2020 study examined how a disproportionate percentage of men or women would affect how AI algorithms diagnose medical images (i.e. X-rays, CT scans, etc.). Researchers found that if an algorithm was trained with a dataset that included only a small number of female patients, it would be more likely to misdiagnose a female patient.9 A 2020 study found that pulse oximeters, devices that are used to measure blood oxygen levels, were 3 times more likely to miss low blood oxygen levels in Black patients when compared to white patients.10 From these results, researchers emphasized the need to consider gender, race, and other forms of bias when creating medical AI algorithms.

Regulation

The FDA is responsible for regulating medical devices. Less than 5% of medical devices are considered “high-risk” and required to prove safety and effectiveness in clinical studies before they can get approved by the FDA. High-risk devices, such as pacemakers or an artificial heart, are defined by the FDA as sustaining or supporting life, are implanted, or present potential unreasonable risk of illness or injury, but not all high-risk devices are required to be proven safe or effective.11 Medical devices that the FDA considers “moderate-risk” do not need to submit data on safety or effectiveness, and are rarely required to submit data from clinical trials.  They are not approved by the FDA but are instead labeled as “FDA cleared.”

Wearable medical devices are considered moderate risk. A moderate-risk medical device is defined as having some risk that must be regulated in order to prevent harm to the user or others. In order to qualify as FDA cleared, a wearable medical device must either encourage healthy behaviors without referencing any particular disease/condition, or promote healthy lifestyle choices that have been shown through data to improve health or quality of life.12,13

Of the previously discussed examples of wearable personal medical devices, all were FDA cleared because they are considered as health-promoting tools that are moderate-risk and non-invasive. But even with this status there is some nuance. The FitBit device itself only needed clearance, but its app to track atrial fibrillation needed FDA approval.14

In the above examples, medical companies went through the FDA review process so they could advertise their products as medical devices that track health data. Not all companies seek FDA review, however. As a result, the FDA sometimes sends warning letters to companies that advertise their product as a medical device but failed to seek approval or clearance from the FDA. For example, in 2021, the baby technology company Owlet stopped selling its Smart Sock–a device that monitors a baby’s vital signs–after receiving a warning letter from the FDA. The Smart Sock had not applied to the FDA for marketing, but was being advertised by the company as a diagnostic health tool.15

HIPAA is the law that protects the privacy of patients’ medical information.  However, the data stored by some of these wearable electronic health devices and apps is not always HIPAA protected and can be used for the industry’s own advantage.16 For example, Fitbit collects personal information such as address, height, weight, and heart rate but does not have to follow HIPAA regulations. This is because they technically are not providing healthcare services and the data are intended for consumer-only use. Therefore, they do not have to abide by the HIPAA policies. Instead, users have to instead rely on Fitbit’s own policy about personal information.16 On the other hand, the Apple Watch is a wearable personal health device that could fall under HIPAA regulation. If a physician and patient use this technology then “any PHI that is recorded or transmitted through the device must be protected and a number of controls must be installed under HIPAA”.17 While these are preventive measures against hackers accessing personal data, it is insufficient. For example, in 2021, 61 million health records from FitBit and Apple Watch users were leaked in a data breach. Data such as the user’s name, gender, age, and geographic location were all exposed, leading many to call for increased data security for wearable devices.18

Needless to say, the protection consumers assume they receive may be misguided so it is highly recommended that consumers do their own research before purchasing these wearable health devices.

The bottom line

Wearable electronic health devices are popular in the U.S. and consumer use is expected to rise even more in the future. These devices can be useful in improving daily physical activity and have possible applications in clinical settings for monitoring and diagnosing patients. Still, wearable electronic health devices do carry risks such as skin irritation, inaccurate electronic health data, privacy breaches, and biased algorithms. While some of these devices are regulated by the FDA, many are not. Moreover, the health data that they produce and emerging AI technologies used for diagnostics are currently under-regulated in the U.S. This means that using these devices carries some risks for the consumer.

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.

References:

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