Aloha MikeS, thanks for asking us your question about the Samsung Galaxy Ring. The advertised Galaxy Ring monitors heart rate and blood oxygen at night and is able to alert you at night, however, these alerts are phone-based push notifications, not audible sounds or vibrations from the ring itself. If you have additional questions for us or if you would like any further assistance, please let us know by reaching out to Support at your leisure. Thank you for choosing Samsung! - Debra