There are actually many kinds of reasons behind this topic. For work and for study can be the main reasons in my mind. For one thing, those adults who are extremely busy with their regular work tend to get up very early in the morning mainly because they have to do it, normally they would work more than 8 hours each day and 2 hours at least on the road. Getting up early is a necessary part of their life, undoubtedly. For another, ordinary student tend to get up early because it is required. More importantly, they are used to it as well. Early in the morning, they study something one or two on different kinds of books, their efficiency would be improved for sure. That is it.