What they track, how they help and what to watch for

Wearable technology has transformed how we monitor and manage personal health. For those focused on heart health, these devices now offer more than fitness tracking — they are tools for early detection, chronic disease management and cardiovascular recovery.

But how accurate are these wearables? Can they detect serious conditions like atrial fibrillation? And how might they help patients avoid hospital readmission?

Dr. Robert Shapiro, an interventional cardiologist with Boulder Heart, recently explored these questions during a community education lecture on wearable devices for heart health. His insights highlight how wearable technology is reshaping preventive and clinical care.

What are wearable devices?

“Wearables are consumer devices that are meant to give health data,” Shapiro said. “They’re not classified as medical devices and don’t undergo the same rigorous FDA approval process. But several companies have conducted solid scientific studies to support their claims.”

The range of available devices is wide — and growing. “If you can think it, they can probably put a sensor in it and get data from it,” Shapiro said. From watches and rings to heart rate monitors and smartphone-connected patches, these tools are increasingly integrated into everyday life.

Some of the most common consumer wearables include:

• Apple Watch

• Fitbit

• Samsung Watch

• Garmin and Polar watches

• KardiaMobile

• Oura Ring

• Smartphone apps and bike-mounted monitors (Garmin, Wahoo)

Most wearables use sensor technology like photoplethysmography (PPG). This uses light to measure blood flow changes in the skin, helping estimate heart rate, heart rhythm and heart rate variability (HRV). However, “PPG sensors are not on all the time, because of battery life, so it does limit the data,” Shapiro noted.

He also noted that while these tools are generally accurate, they are better at tracking heart rate at rest than during physical activity. “One of the limitations of these devices is their accuracy on heart rate,” he said. “They don’t do as good of a job when you’re exercising as opposed to just resting — especially during AFib.” That said, “different devices have very similar accuracy levels.”

Understanding heart rate variability

HRV measures the variation in time between heartbeats and is increasingly used as a marker of physical and emotional health. Shapiro said high HRV can indicate strong cardiovascular fitness and good recovery, while lower HRV may signal stress or illness.

“Things that contribute to a high HRV include increased fitness, better sleep quality and lower psychological stress,” he said. “It’s also generally higher in biological males. Things like overexertion, systemic illness and stress decrease it. It tends to decline gradually over time.”

Although HRV isn’t diagnostic on its own, it’s a valuable trend metric — especially when paired with other health indicators.

Atrial fibrillation detection

Atrial fibrillation, or AFib, is an irregular heart rhythm that increases the risk of stroke and heart failure. It becomes more common with age. “Atrial fibrillations are more common as people get older,” Shapiro said, “and people [over 40] have a 1 in 4 chance of having AFib in their lifetime.” (Source)

Wearables offer a significant advantage in detection, especially for people who don’t have consistent symptoms or who go in and out of rhythm. “Wearables can look for AFib much more frequently than a medical device that is only worn for short periods of time,” Shapiro said. “That makes them incredibly useful for people with known AFib, especially to help track how often they go in and out of it and what their heart rate is at those times.”

During a study using ECG patch monitoring, about 18 percent of participants were in atrial fibrillation 100 percent of the time — showing how often the condition can go unnoticed without continuous monitoring. (Source)

Shapiro noted that “some of our guidelines are coming around to the idea that wearable devices can be very helpful. They have data that shows that if people even randomly check their device, they can detect AFib more easily than if they didn’t have one. These devices make it easier to find when people have AFib.”

And detection matters. “Detecting AFib can help prevent stroke,” he emphasized. “That’s the real power of finding it early.”

Supporting recovery after a heart attack

Wearables are also proving valuable for cardiac recovery. In the MiCORE trial, patients used a combination of an Apple Watch, blood pressure monitor and smartphone app to manage recovery after a heart attack. The app guided patients with educational videos, daily care plans and medication reminders.

“Watching oxygen levels and seeing them decline could alert us to decompensation early,” Shapiro said. “These tools give us a way to help heart failure patients stay healthier and out of the hospital.”

Encouraging healthy habits

In addition to clinical applications, wearable devices encourage better day-to-day health. Step tracking, heart rate monitoring and sleep data can all reinforce positive habits and support long-term cardiovascular wellness.

“Wearable devices can help show how much activity people are actually getting,” Shapiro said. That insight matters — especially when paired with health goals. “VO2 max improving can be a clear sign that heart health is improving,” he added, referring to the maximum rate at which the body can use oxygen during exercise, a strong marker of cardiovascular fitness.

National guidelines recommend at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous activity each week. For many people, wearables offer accountability and motivation to meet those targets.

“Increased activity helps lower mortality,” Shapiro said. “That’s where we see these benefit the larger population the most.”

Some devices also help detect sleep apnea — a known contributor to heart disease. Others provide feedback on training loads and stress recovery, making them useful for both heart patients and athletes alike.

The future of wearables and AI

As wearables evolve, artificial intelligence is opening new doors. By combining data from wearables with AI analysis, researchers have been able to predict hospitalizations with impressive accuracy. “I think AI is the future of this,” Shapiro said. “It allows us to take all the data these devices are collecting and find patterns we might otherwise miss.”

AI-driven insights could support earlier intervention, tailor treatment plans and eventually help clinicians provide more personalized cardiovascular care.

Limitations and considerations

Like any tool, wearables have limitations. Heart rate data may be less reliable during arrhythmias or intense activity. Devices do not collect data while charging or not in use. Data accuracy also depends on device placement and fit.

Wearables offer extensive access to health information — but that constant stream of data can sometimes be overwhelming. “The amount of data can be overwhelming to the user,” Shapiro said. “Some studies show that wearable devices increase anxiety in patients. And it can be overwhelming to your providers if you bring in reams of data and they only have limited time to spend with you.” (Source)

Despite this, many users find reassurance in tracking their heart metrics. “More people feel safe if they’re checking their heart rate or heart rhythm than not,” he added. “You have to balance the good and the bad.”

For those prone to worry or unsure how to interpret the information, that balance is especially important. Wearables work best when paired with clinical guidance — helping patients stay informed without becoming overwhelmed.

It’s worth noting that while Medicare reimburses for remote physiologic monitoring (RPM) using approved medical-grade devices, most consumer wearables — like those purchased in stores or online — are not covered. As the clinical utility of wearables becomes more widely validated, insurance coverage may expand in the future. Currently, some wearables can be reimbursed by Health Savings Accounts (HSA) and Flexible Spending Accounts (FSA).

Take the next step for your heart health

Wearables are not a replacement for medical care — but they are powerful tools for understanding your heart, forming healthy habits and managing chronic conditions. From rhythm monitoring to recovery support and personalized feedback, these devices can make a meaningful impact.

“These tools can help keep people healthy and out of the hospital,” Shapiro said.

If you have questions about using wearables to support your cardiovascular health, talk with your primary care provider or connect with a cardiologist at Boulder Heart. They can help you determine which devices may offer the most value for your health goals — whether you’re managing a condition like AFib, recovering from a cardiac event or simply aiming to stay heart-strong as you age.

For more information about heart care or to schedule an appointment with Boulder Heart, call 303-442-2395.

Watch the full lecture here: