Patients are showing up to appointments armed with heart rate graphs, variability scores, and spike alerts from their smartwatches — and clinicians need to know what to do with that data. At France's 19th National Congress on Sports Medicine and Traumatology, Dr. Stéphane Doutreleau of Grenoble Alpes University Hospital offered a practical framework for interpreting wearable device data in clinical settings.

The key issue is reliability. Chest strap ECG monitors remain the gold standard, while optical sensors in smartwatches (which use photoplethysmography, or PPG) are far more prone to error — especially during high-movement activities like running or cycling, where heart rate can be underestimated by dozens of beats per minute. Heart rate variability (HRV), another popular wearable metric, is only meaningful when measured at rest, under consistent conditions, and tracked over time — a single reading tells you very little.

Key Takeaways:

• Don't dismiss heart rate "spikes" as artifacts — some represent real arrhythmias and warrant ECG or Holter confirmation
• HRV trends (not single values) are what matter; always compare a patient to their own baseline
• Ask patients which device they used and under what conditions before drawing any clinical conclusions

Why it matters: As wearables become ubiquitous, clinicians who can critically interpret — rather than ignore or over-trust — this data will be better equipped to catch real cardiac events early and avoid unnecessary alarm over measurement noise.