Smartwatches and fitness trackers have wormed their way into the daily lives of millions of people. Some sit on wrists or fingers, counting steps, monitoring sleep, and occasionally interrupting a meeting or movie with an alert that something in our bodies may be worth noticing. But how much can these devices actually tell us about heart health?
During a recent Instagram Live conversation, cardiologist Jennifer Haythe, MD, spoke with Isaac George, MD, heart surgeon and Director of the Structural Heart and Valve Center, and Hirad Yarmohammadi, MD, electrophysiologist specializing in heart rhythm disorders, to unpack the ins and outs of wearable health tech.
Watch the full discussion here:
A New Kind of Awareness
At their best, wearables act as a kind of daily mirror for the body. They track the core basics like heart rate, activity levels, sleep patterns, and sometimes even oxygen levels. And over time, as data often does, those numbers begin to form patterns.
“I got Covid really early, and I was sick. I was sent to a separate apartment, and I actually used my Apple Watch,” Dr. George said during the chat. “I tracked my heart rate, and I tracked my O2 saturation. I noticed some clear trends that actually helped me understand my body.”
That kind of real-time feedback can change how people think about their bodies. When heart rate, activity levels, and sleep appear as visible metrics, we often become more attentive to them. “You see alerts, the little circles. These circles are really important,” he continued. “I see them and subconsciously say, all right, you know what? I want to close my rings. It’s activating.”
At the same time, more data doesn’t always mean more clarity. “Very commonly, I see a lot of patients with anxiety because of the notifications they receive from the watch,” Dr. Yarmohammadi said.
The technology behind these alerts relies largely on optical sensors (like a visible green light on the underside of many watches) that track blood flow through the wrist. Some devices can also record an electrocardiogram (ECG) on demand. While these tools are increasingly sophisticated, false alarms happen, and certain motions, poor contact with the skin, or normal variations in heart rhythm can sometimes be interpreted as abnormal.
“Although they are a very advanced piece of technology, they’re not perfect,” Dr. Yarmohammadi continued.
What Wearables Do Well
Despite those limitations, wearables have proven useful in tracking the trend of a heart rate. If a resting heart rate begins climbing unexpectedly or exercise tolerance suddenly drops, those changes can provide an early signal that something in the body has changed.
Heart rhythm monitoring can also be valuable. For those with known arrhythmias like atrial fibrillation, wearable ECG recordings can sometimes help physicians confirm whether symptoms represent a recurrence or even help postoperatively. “If someone tells you, hey, my Apple Watch shows that I'm in atrial fibrillation, that's very helpful,” Dr. Haythe said. “This is an extension of us in some ways.”
One theme rang true over and over throughout the discussion: it’s all about the patterns.
Heart rate variability, a metric many fitness apps highlight, reflects how the autonomic nervous system regulates the heart. In general, more variability tends to signal better cardiovascular resilience, but its value lies in watching how it changes. “The key is trends,” Dr. Yarmohammadi added. “If something consistently moves in the wrong direction, that’s meaningful.”
They Can’t Do It All
“They can’t diagnose a heart attack,” Dr. George said. “They can’t diagnose a stroke.”
Routine medical tests like EKGs, imaging studies, and stress tests remain the foundation of cardiovascular care. While wearables may eventually play a larger role as AI improves its ability to interpret data, for now, they function best as tools that complement clinical care.
The greatest takeaway? “If you don’t feel good, go to the doctor,” says Dr. Haythe. “Your watch is not the final authority. The goal isn’t to watch your heart constantly. It’s to live well with it.”
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