Wearable electronic devices, systems, and methods for monitoring sleep are described. In one method, motion sensor values of the current motion of the electronic device are acquired and the change in motion intensity of an electronic device is calculated by comparing motion sensor values over two or more time periods. If the change in motion intensity fits a predetermined pattern, it is determined whether the electronic device is currently being worn. If it is determined that the electronic device is currently being worn, sleep monitoring is performed.本發明闡述用於監控睡眠的穿戴式電子裝置、系統、及方法。在一種方法中，獲取電子裝置的目前運動的運動感測器值並藉由對兩個或更多個時間週期內的運動感測器值進行比較來計算電子裝置的運動強度的變化。若所述運動強度的變化符合預定型式，則判斷目前是否正在穿戴所述電子裝置。若確定目前正在穿戴所述電子裝置，則執行睡眠監控。
