The Apple Watch Series 9, Series 10, and Watch Ultra 2 have received FDA approval for sleep apnea detection. The feature uses the on-board accelerometer to track sleep patterns and detect potential sleep apnea. It requires 10 nights of sleep tracking data over a 30-day period to determine the risk of sleep apnea. The feature is not a diagnostic tool, but rather a prompt for users to seek a formal diagnosis from a healthcare provider.