Just a heads up on the Garmin sleep monitor its next to useless if u have any type of heart condition eg a heart blockage or athletes heart.
I have a first degree heart blockage which causes a low heart rate down to 30bpm some times less.
Last night when watching Tv my heart rate was a steady 40/42 beats per minute for upto an hour since not moving my arm for that time the Garmin sleep software assumed I was in a deep sleep I can assure you I was not.