Possible to track sleep without having sleep on?

Long time fitbit user here. Trying out the apple watch, the sleep tracking looks to be separated from the watch app and if you try to track your sleep it makes you select a sleep schedule and makes your watch unresponsive during that schedule. Is there a way for it to track sleep without having to put a sleep schedule? I dont need to be told when i am allowed to look at my watch. None of my other trackers have ever done this. I cant find a way to make it track sleep without that schedule set.