Apple Watch Ultra 4 vs Garmin Fenix 9 Pro: Both watches nailed my accuracy test
techradar.com Oct 10, 2026

Apple Watch Ultra 4 vs Garmin Fenix 9 Pro: Both watches nailed my accuracy test

AI-summarised brief · reviewed before publication

A reviewer tested the Apple Watch Ultra 4 and Garmin Fenix 9 Pro by wearing both watches during a 30‑minute, hilly run while a chest‑mounted ECG heart‑rate monitor served as the benchmark. The Apple Watch’s new Health Sensing System was evaluated against Garmin’s long‑standing accuracy. The test focused on average heart‑rate differences, with a margin under 5 bpm considered negligible. Both devices were compared to the electrical monitor to assess consistency and reliability across different algorithms. The article details the methodology and the resulting accuracy figures for each smartwatch.

💡 Why It Matters

  • · The comparison shows how consumer‑grade wearables stack up against medical‑grade monitoring, informing athletes and health‑conscious users about which device delivers trustworthy data for training and wellness.