What Your Smartwatch Can Tell You About Your Heart

In today’s connected world, many of us glance at our wrists for more than just the time. From step tracking to sleep insights, wearable devices have become part of our daily routines and can provide valuable insights into our health. But one of their most talked-about features is heart monitoring, especially the ability to detect irregular rhythms like atrial fibrillation (AFib).

If you're curious whether these alerts are reliable and what to do if you receive one, our board-certified cardiologist and electrophysiologist, Marvin Lu, MD, shares the details to help you better understand what these devices can tell you about your heart.

Understanding How Smartwatches Monitor Your Heart

Smartwatches use advanced technology to estimate your heart rate and rhythm, often in ways you might not even notice.

“They work primarily through photoplethysmography — a process of emitting light from a small sensor onto the skin and detecting variations in light reflection that correspond to blood flow with each heartbeat,” Dr. Lu explains. “This allows the smartwatch to determine your pulse rate by converting it to beats per minute.”

Some devices also offer electrocardiogram (ECG) capabilities, which take things a step further. “The smartwatch ECG allows evaluation of electrical activity of the heart by using two electrodes,” he says. “With your wrist touching the back of the watch and your opposite hand touching the crown or side button, you’re able to complete a circuit and collect an electrical tracing of your heart.”

Can Wearables Reliably Detect Irregular Rhythms?

When it comes to whether wearables can reliably detect irregular rhythms, the short answer is yes, with some important limitations.

“[These devices are] able to determine if something is not normal, including atrial fibrillation and other common arrhythmias,” Dr. Lu says. “However, sometimes it will have difficulty determining which specific abnormal rhythm is present.”

In other words, your smartwatch can be a helpful early warning system, but it’s not a definitive diagnosis.

The Cause of Irregular Heartbeat Alerts

Getting an alert can feel alarming, but not all irregular rhythms are cause for concern.

“Atrial fibrillation, premature atrial contractions and premature ventricular arrhythmias are the most common arrhythmias that trigger abnormal notifications,” Dr. Lu explains. “They are not always concerning if infrequent.”

That said, patterns matter. “If notifications are getting more frequent and the duration is getting longer, it's important to discuss these findings with your physician,” he adds.

Seeking Medical Care

If you receive an occasional notification without symptoms, it may not be urgent. But certain signs should prompt a closer look.

“If the notifications happen more frequently and/or if you develop symptoms such as palpitations, chest pain, shortness of breath, dizziness or lightheadedness, you should seek medical attention,” Dr. Lu advises.

Starting with your primary care provider is often a good first step, but depending on your symptoms or device findings, you may be referred to a cardiologist or an electrophysiologist, a specialist in heart rhythm disorders.

Why Clinical Confirmation Matters

While wearable technology is impressive, it’s still just the first step. “It’s extremely important to do confirmatory diagnostic testing prior to formulating treatment plans,” Dr. Lu emphasizes. “Wearable devices are screening tools geared to be more sensitive rather than specific.”

That means they’re designed to catch potential issues, even if it means sometimes flagging something harmless. “Overdiagnosis can lead to overtreatment and prescription of medications that carry certain adverse effects,” he explains.

Clinical tests, such as medical-grade ECGs, Holter monitors or other diagnostics, help ensure that any treatment plan is both accurate and appropriate.

Should You Wear a Smartwatch for Heart Monitoring?

If you're wondering whether to start wearing a smartwatch or other wearable device to monitor your heart, the answer isn’t one-size-fits-all.

“It depends on the patient,” Dr. Lu says. “There are patients where more information may be detrimental, and there are patients for whom more information is definitely helpful.”

One thing is clear: these devices are here to stay. “Wearable devices have certainly increased our awareness of rhythm disorders,” he notes. “They've also caused some confusion if not confirmed with more robust diagnostic testing.”

As for which device to choose? “It doesn't matter which device you pick, as the technology is similar across the majority of them,” he adds.

Turning Data Into Meaningful Care

As wearable technology continues to evolve, it’s changing the way we think about preventive health, especially when it comes to the heart.

“We can't ignore the fact that these technological advances will continue to improve and will be a part of our daily lives,” Dr. Lu says. “We should welcome them with open arms.”

But interpreting that data is just as important as collecting it. “It's our responsibility, as part of your healthcare team, to help interpret the information that these technologies provide,” he shares.

Your Heart Is in Good Hands

A smartwatch alert doesn’t have to leave you feeling uncertain. It can be the first step toward better understanding your heart health. If you’ve received an irregular heartbeat notification or are experiencing symptoms, our heart and vascular specialists are here to help support your next steps.

Learn more about our heart and vascular care services and connect with a specialist today.