Does the Soundcore Liberty 4 Pro Heart Sensor Actually Work? (Test Results)
Anker's new Soundcore Liberty 4 Pro earbuds are making waves for their noise cancellation, but there's one feature that has everyone confused: the Heart Rate Sensor.
Why do earbuds need to track your heart? And more importantly, does it actually work?
We tested the 7-sensor system to see if this is a legitimate fitness tool or just marketing hype.
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How It Works
Inside the right earbud, Anker has placed a tiny PPG sensor (similar to what is on the back of an Apple Watch). It shines a light into the skin of your ear canal to detect your pulse.
You can view your heart rate in real-time via the Soundcore App, which tracks it during workouts.
The Accuracy Test
We compared the Liberty 4 Pro's readings against a dedicated chest strap monitor during a 30-minute run.
- Resting Heart Rate: Spot on. It matched our medical-grade equipment perfectly.
- Running (Steady State): Surprisingly accurate. It stayed within 2-3 beats per minute of the chest strap.
- HIIT / Sprinting: This is where it struggled slightly. During rapid spikes in heart rate, the earbuds lagged about 5-10 seconds behind the chest strap.
Is it Useful?
Yes, if you hate smartwatches.
If you don't like wearing a watch while you run or lift weights, this is a fantastic alternative. It syncs with the app to give you a "Wellness" report, tracking your stress levels and workout intensity.
The Verdict
It's not just a gimmick. The 7-sensor system (which also helps with noise cancellation adjustment) makes these some of the most advanced earbuds you can buy for under $150.