Energizers are activities used in workshops and group situations to help participants be more alert and active; they can also be an important way of people getting to know and understand one another. There are many different energizers of varying length, complexity, exertion and ingenuity. They need to be enjoyable and feel safe, so should always be used in a way that is sensitive to factors such as culture, gender, physical ability and group dynamics. They can be particularly useful at the start of the day, when people are still getting to know one another, and after lunch, when sleepiness can set in.