Function Explanation：
1. Yes, Support, which can be set via Mi Fit APP. There are four modes: turn off detection, assisted sleep detection, automatic heart rate detection, automatic heart rate detection + assisted sleep detection.In different modes, the band battery life is different.
2. When the automatic heart rate detection is turned on, it will detect the heart rate throughout the day and significantly reduce the battery life. The detection frequency can be set by owner: 1 minute, 5 minutes, 10 minutes and 30 minutes.
Setting path：
Mi Fit APP：My->Mi Band->heart rate detection->select mode to set the frequency