Can smartwatches detect early signs of worsening heart failure?

by | Mar 25, 2026 | News, Research / Technology

New research from University Health Network, featuring TRANSFORM HF members Dr. Heather Ross, Dr. Chris McIntosh, Dr. Yas Moayedi, and Will Gao, shows that wearable technologies, such as the Apple Watch, can help monitor heart failure by providing early signs of deteriorating health – often days to weeks before unplanned medical care is needed.

Through the Ted Rogers Understanding Exacerbations of Heart Failure study (TRUE-HF) published in Nature Medicine, the research team developed an AI model that uses Apple Watch data to estimate daily peak oxygen uptake (pVO₂) – a key measure of cardiorespiratory fitness.

The study, Remote monitoring of heart failure exacerbations using a smartwatch, featured on the cover of Nature Medicine. Illustration by Katie Yost ©2025

The Findings

When participants went about their daily routines while wearing an Apple Watch, smartwatch-based fitness estimates closely matched clinical test results – and a 10% drop in predicted pVO₂ was associated with a threefold increase in risk of an unplanned medical event.

These results underscore the potential for wearable technology to provide a better picture of a patient’s day-to-day heart health and support timely medical intervention.

Congratulations to the entire research team – Heather Ross, Chris McIntosh, Yas Moayedi, Will Gao, Farid Foroutan, Bhavish Verma, Ben Kim, Enza De Luca, Margaret Brum, Darshan H. Brahmbhatt, Joe Duhamel, and Anne Simard – for this incredible work!

Read more via UHN Research News.

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