I will tell you what I have learned myself. For me, a long five- or six-mile walk helps. And one must go alone and every day. I have done this for many years. It is at these times I seem to get re-charged. If I do not walk one day, I seem to have on the next what van Gogh calls "the meagerness.""The meagerness," he said, "or what is called depression." After a day or two of not walking, when I try to write I feel a little dull and irresolute. For a long time I thought that the dullness was just due to the asphyxiation of an indoor, sedentary life (which all people who do not move around a great deal in the open air suffer from, though they do not know it).

 ― Brenda Ueland, If You Want to Write: A Book about Art, Independence and Spirit