I took it to my wife just to monitor sleep. She is a nursing mother, sleeps badly, wanted to measure. On the first day I woke up 5 times a night, fed. The bracelet showed a very deep sleep, better than 98% of people, did not determine a single awakening. The second night, the little one fell ill, 6 times a night I WENT TO THE KITCHEN for medicine, the result is not a very sound sleep, better than 80% of people, NOT A SINGLE awakening)))) At the same time, the beginning and end of sleep measures See full review