Anker's Soundcore Sleep Earbuds 4 Pro Add In-Ear Health Sensing and Adaptive Sleep Audio

Anker's Soundcore Sleep Earbuds 4 Pro, arriving in November at $349.99, use an in-ear PPG (photoplethysmography) sensor to track heart rate, HRV, stress, and fatigue. That data drives BioSync, which plays adaptive soothing audio to help users fall asleep — shifting the device from passive sound masking toward active sleep intervention. The standard model ($229.99, October) drops the sensor.