New Smartwatch Metric Could Transform Heart Health Monitoring

New Smartwatch Metric Could Revolutionize Heart Health Monitoring

In the world of cardiovascular health, monitoring and predicting risk factors accurately is paramount. Traditionally, wearable technologies like smartwatches have provided valuable insights through simple metrics such as daily step counts and average resting heart rates. While these metrics offer important information about general health, a new and promising metric is being developed that may provide a more accurate and reliable indicator of heart health. This new metric combines daily step counts with heart rate data to give a more holistic view of cardiovascular fitness.

At the American College of Cardiology (ACC) Scientific Session 2025, Zhanlin Chen, a medical student from Northwestern University in Chicago, Illinois, presented groundbreaking research that could reshape how we approach heart health monitoring. By integrating two key health data points—steps and heart rate—Chen and his colleagues have identified a new metric that may more effectively reflect a person’s heart health than either measure on its own.

The Problem with Traditional Metrics

Daily steps have long been considered a reliable predictor of cardiovascular health. The more steps a person takes, the more likely they are to be physically active, which is generally associated with better heart health. However, as Chen pointed out, steps alone are an indirect indicator of heart health. “It only shows how much we move,” he explained. "It doesn’t necessarily tell us how hard the heart is working while we move." For instance, two individuals may both walk 10,000 steps a day, but one may experience a significantly higher heart rate, suggesting their heart is working harder than it should be during activity. This could be an early warning sign of cardiovascular problems that wouldn’t be apparent from step count alone.

Moreover, relying solely on heart rate as a standalone measure can also be misleading. A high heart rate outside of physical activity can indicate stress, dehydration, or other underlying health issues. Chen’s insight was to combine these two seemingly disparate metrics—daily steps and heart rate—into a single value that could provide a deeper, more nuanced understanding of heart health.

A New Metric: Integrating Heart Rate and Steps

Chen’s new metric works by dividing a person’s average daily heart rate by the number of steps they take per day. This combination of heart rate and step count could provide a clearer picture of how efficiently the heart is working during daily activities. The rationale behind this approach is simple: the higher the heart rate per step, the more the heart is working to sustain activity. By comparing individuals across different activity levels, this combined metric allows for more accurate predictions about their cardiovascular health.

This new metric was evaluated using data from over 7,000 adults who participated in the All of Us research program, a nationwide study supported by the National Institutes of Health (NIH). Participants provided data from Fitbit smartwatches, along with electronic health records, to assess their heart health. The results were striking: individuals with higher daily heart rate per step—those in the top 25%—had significantly worse cardiovascular outcomes compared to those in the lowest quartile.

Key Findings from the Study

The study revealed that individuals with elevated daily heart rate per step were at a higher risk of several cardiovascular conditions. Specifically, they were:

• Twice as likely to develop type 2 diabetes
• 1.7 times as likely to experience heart failure
• 1.6 times as likely to have high blood pressure
• 1.4 times as likely to suffer from coronary atherosclerosis

Interestingly, no direct association was found between elevated heart rate per step and the risk of stroke or heart attack. While this metric appears to be a strong predictor of certain cardiovascular conditions, further research will be necessary to understand its broader applications.

Expert Opinions: A Promising Sign for Wearable Technology

While the findings are promising, Dr. Eugene Yang, a cardiologist at the University of Washington in Seattle, cautioned that the new metric needs validation in more granular, randomized studies. Despite this, Dr. Yang recognized the potential of wearable technology, like smartwatches, in revolutionizing healthcare. He highlighted that the ability to accurately measure various health parameters—blood pressure, heart rate, oxygen saturation, daily activity, and even sleep—could significantly improve our understanding of cardiovascular risk. “We’re entering a really exciting time,” Yang said. “If we can measure so many things accurately, that will be a much stronger predictor of risk.”

This new combined metric could open the door to more individualized and effective cardiovascular risk assessments. The data gathered from wearables can offer real-time insights into a patient’s daily habits, providing physicians with valuable information beyond what is typically captured during office visits.

The Future of Heart Health: Wearables as Tools for Prevention

Zhanlin Chen hopes that this new metric will eventually be incorporated into clinical guidelines for cardiovascular disease risk estimation. Currently, traditional heart disease risk models do not account for real-time fitness data or other lifestyle factors. By incorporating wearable data, clinicians could gain a more comprehensive view of a patient's heart health, which may lead to earlier interventions and better personalized care.

“This could have significant implications for how we estimate heart disease risk,” Chen said. “It might translate into changes in medical interventions and risk stratification, as well as the way we approach screening and prevention.”

The integration of wearables into heart health monitoring could also reduce the reliance on infrequent and sometimes inaccurate in-office assessments. Wearables allow continuous, real-time tracking, making it easier to detect early signs of cardiovascular problems before they develop into serious conditions.

Conclusion: Wearables Could Be the Future of Heart Health Monitoring

The integration of heart rate and daily steps into a combined metric is a promising advancement in wearable technology. By offering a more accurate and comprehensive picture of cardiovascular health, this new metric could help clinicians better predict and manage heart disease risk. As more research is conducted, it’s likely that wearable devices will become an essential part of cardiovascular risk assessment and prevention. The combination of real-time data from devices like smartwatches, alongside clinical expertise, could help improve heart health outcomes for millions of people around the world.

As wearable technology continues to evolve, we can expect to see even more sophisticated tools for monitoring health, providing physicians and patients with actionable insights that could lead to better prevention, earlier detection, and more effective treatment of heart disease.