Yes, the Xiaomi Smart Band 9 can record sleep. It offers extensive sleep tracking functions, including measurement of total sleep time, individual sleep phases (light, deep and REM) and average heart rate and oxygen saturation levels during sleep. In addition, sleep is rated with a score and a word grade, and there are comparisons with previous nights and other users in the same age group. After at least seven consecutive nights, a "sleep animal" is also assigned, which represents the sleep character and sleep rhythm.