Wearable health devices such as smartwatches and bands are more than fitness trackers. Many also can monitor your cardiovascular health.

Experts say that these heart-health devices can help you stay aware of, and even improve, your cardiovascular health — as long as you understand their shortcomings, too.

• Heart Rate Devices measure your heart’s electrical activity or use optical sensors to measure your pulse. They also can track heart-rate variability.
• Irregular Rhythm or Atrial Fibrillation (Afib) Alerts Some devices use built-in algorithms to flag irregular rhythms that may be afib.
• Daily Steps and Activity It’s common for devices to track step counts, distance, and active minutes to measure your exercise, and they also may measure intensity.
• Calories Burned Devices may estimate how much energy you expend, though accuracy may differ depending on body placement — a wrist monitor may show a different reading from one on your ankle.
• Sleep Patterns Sleep is good for your heart, and wearables can track when and how long you sleep as well as how well you sleep.
• Blood Oxygen Saturation Some devices estimate blood oxygen levels using light-based sensors.
• Stress Level Devices may offer composite scores based on many of these other data points to indicate if your body is under stress or is recovering.

Technology has evolved to the point where wearable devices can show you heart-health warning signs and where your efforts to improve heart health are paying off. But not all of these heart health tracking features have been recognized as reliable by experts.

Detecting Heart-Rhythm Issues

One of the strongest features of wearable devices is their ability to identify irregularities in your pulse.

• Accelerometer sensors, which detect motion and acceleration
• Electrocardiograph sensors (ECG), which record your heart’s electrical activity
• Photoplethysmograph sensors (PPG), which use infrared sensors to track changes in blood volume

They also may include additional sensors, such as gyroscopes or thermometers, that can provide heart-related feedback.

“These data are the most widely used for diagnosis and management of cardiac arrhythmias, most notably atrial fibrillation,” says Nazem Akoum, MD, a cardiologist at the Heart Institute at the University of Washington Medical Center in Seattle.

A smartwatch isn’t your doctor, however. If your device repeatedly flags an irregular rhythm, or if you have symptoms such as palpitations or shortness of breath, call your doctor.

Tracking Activities 

Understanding Sleep Patterns

Although this information can help pinpoint potential sleep disorders, wearable devices are not a replacement for polysomnography, or a laboratory sleep study. If you suspect you have sleep issues because of what your device tells you, talk to your doctor about next steps in determining a potential diagnosis.

Monitoring Oxygen Levels

Dr. Akoum says that this feature also can be useful in detecting symptoms of a breathing problem such as obstructive sleep apnea. If left untreated, sleep apnea can increase your risk of developing an irregular heartbeat or high blood pressure, which can lead to heart failure or a stroke.

Detecting Variations in Heart Rate and Stress

It is an inexact science, however.

“I wouldn't say heart rate variability is something that people should fixate on, which a lot of people tend to do, because a lot of things influence it,” says Paul Leis, DO, a cardiologist and an assistant professor of medicine at the Icahn School of Medicine at Mount Sinai in New York. “Even a simple illness can change heart rate variability readings, and that can spiral into unnecessary worry.”

Reading Blood Pressure 

Manufacturers may claim that devices such as watches keep track of your blood pressure, but these measurements aren’t always reliable.

Wearable devices can be useful tools for heart health management. But to use them effectively, you should be aware of what they can and cannot measure well.

Potential Benefits

“Wearables can be good motivators and change habits if we are willing to commit to using them,” Akoum says.

Benefits include:

• Uncovering Serious Problems Wearables may clue you into a health issue such as afib or hypertension before symptoms arise. Dr. Leis says he has had patients who didn’t know they had an irregular heartbeat until their device alerted them to it. “When we followed up with formal ECG monitoring, the results correlated very well,” he says.
• Providing Data for Doctors Data that wearable devices collect over time can help your doctor understand your potential condition better than during a single visit. “Objective information collected by wearables can be valuable in almost any setting if the information is correctly interpreted in context,” says Calum MacRae, MD, PhD, a member of the Mass General Brigham Heart & Vascular Institute in Boston.
• Promoting Exercise Not only are people who use wearables more likely to take more steps daily, but those who take at least 7,000 steps daily also reduce their risk of heart disease by as much as 25 percent.

  [11]

   Devices’ notifications or activity reminders also can help with accountability. “This simple feedback can help with goal-setting and motivation, (which is) important, since regular physical activity is one of the most effective ways to prevent heart disease,” says Krasimira Mikhova, MD, a cardiac electrophysiologist at Barnes Jewish Hospital in St. Louis.
• Monitoring Recovery Your healthcare team can use your device to monitor your progress, particularly during cardiac rehabilitation if you have heart disease. Research shows that wearables used in tandem with rehab programs can help people stick with those programs.

  [12]

Limits and Drawbacks

If you are considering a wearable device, it’s important to understand their potential risks.

• Variation Between Models Not all smartwatches or workout bands have the same features or technology. Research has shown that some may underestimate heart rate or provide inaccurate blood oxygen levels.

  [13]

  [14]

   “Additionally, most wearables do not provide continuous rhythm monitoring,” Dr. Mikhova says. “As a result, they may miss intermittent arrhythmias and are not 100 percent sensitive for detecting irregular heartbeats.” If you feel a wearable device might help your condition, ask your doctor for suggestions on what specific features to look for.
• Misinterpretation of 'Normal' Just because a wearable says that certain readings are okay doesn’t mean that they are. Devices should not replace a medical diagnosis, and they may not be appropriate for people with advanced heart issues. “The technology has limitations and may not capture the nuances of more severe disease,” says Mikhova, adding that wearables also cannot predict a heart attack. 
• Cause of Anxiety There is such a thing as too much information. “Some individuals — particularly those with underlying anxiety — may become overly preoccupied with the constant flow of health data” from these devices, Mikhova says. “This can lead to unnecessary worry or overuse of healthcare resources.”
• Cost It’s no secret that smartwatches and similar devices can be pricey, and insurance does not usually cover them. Check if your device requires a separate paid subscription service to access the information you want.

FDA-cleared features may include:

• ECG recordings to help detect afib
• Heart rhythm notifications that use optical pulse signals to flag possible afib
• Pulse oximetry estimates for blood oxygen levels

FDA clearance does not mean that the device can diagnose or rule out heart disease, however, or that all features on a device are cleared or provide accurate information.

You can check the FDA’s database for devices with specific features that have received clearance or approval.

“Anyone who might benefit from understanding their own personal performance over time is likely to benefit from wearables,” Dr. MacRae says. 

Wearable devices may be valuable if you have a higher risk of heart disease because of diabetes, obesity, high blood pressure, or a family history of poor heart health. They can help pinpoint changes in heart health that may warrant further investigation, Mikhova says. 

Early detection of afib, for example, could prevent complications such as a stroke.

“For people with known or suspected atrial fibrillation, wearables can be especially useful,” Mikhova says. “Irregular-rhythm alerts may prompt timely evaluation and diagnosis, while those already diagnosed can use wearables to monitor atrial fibrillation burden (the percentage of time spent in the arrhythmia).”

This information from a wearable could help your healthcare team understand your condition better over time, Leis says, rather than relying on a single ECG reading during a doctor visit.

If you are looking to track your exercise routine, maintain your diet, or simply keep an eye on your heart health, a wearable device also may be worth considering. Leis says that your doctor can explain each reading and how it relates to your overall health.

• Smartwatches and other wearable devices can identify potential heart issues such as irregular heart rhythms, but they should not replace professional medical evaluations.
• Devices can track data points such as your heart rate, oxygen level, and sleep quality that can help you and your doctor understand components of your heart health.
• Although wearables may be great if you want to track your physical activity and watch for potential red flags, their accuracy can vary — and they may contribute to anxiety issues.
• If you have potential risk factors for heart disease and are comfortable tracking your health metrics, wearables can be a good way to gather information to help you and your doctor.