Smartwatches flag heart risk
A Nature Medicine–reported study finds consumer smartwatches can identify early signs of worsening heart health and predict increased risk of hospitalization — a growing case for wearables in preventative care. (newswire.ca)
The paper, titled “Remote monitoring of heart failure exacerbations using a smartwatch,” was published online in Nature Medicine on March 20, 2026 and lists investigators from the Ted Rogers Understanding Exacerbations of HF (TRUE‑HF) study at UHN’s Peter Munk Cardiac Centre. (nature.com) Researchers collected free‑living Apple Watch data over a median 94.5‑day follow‑up and trained a deep‑learning model on 154 patients with a held‑out validation set of 63 patients (46 women/108 men in training; 24 women/39 men in validation). (nature.com) The model produced a wearable‑derived daily pVO2 estimate that correlated with in‑clinic CPET‑measured pVO2 with a Pearson’s r = 0.85, indicating strong agreement between the smartwatch biomarker and the gold‑standard exercise test. (nature.com) Quantitatively, each 10% drop in the wearable‑derived daily pVO2 was linked to a 3.62‑fold higher hazard of an unplanned healthcare event (95% CI 1.37–9.55; P < 0.01), with those events occurring at a median of 7.4 days after the first 10% decline. (nature.com) An external validation using an All of Us Research Program cohort and a reduced‑sensor variant of the model showed an association with unplanned healthcare use (HR 1.32, 95% CI 1.03–1.69; P = 0.03) and a longer median lead time of 21 days to events in that dataset. (nature.com) The study was led from UHN’s Peter Munk Cardiac Centre under the TRUE‑HF program and the team has registered a prospective follow‑up (TRUE‑HF2) to further validate wearable‑derived fitness estimates against clinical outcomes. (uhn.ca) (clinicaltrials.gov)
