It is true that a man’s whole life may be regarded as his prayer. Ordinarily, what a person does is an expression of their intent, and their intent is the focusing of their desire, and their desires are the prayers of their heart. But such explanations are far from satisfactory. There is no argument needed for the necessity of taking time out for being alone, for withdrawal, for being quiet without and still within. The sheer physical necessity is urgent because the body and the entire central nervous system cry out for the healing waters of silence. 
One could not begin the cultivation of the prayer life at a more practical point than deliberately to seek each day, several times a day, a lull in the rhythm of daily doing, a period when nothing happens that demands active participation. It is a wonderful way with which to begin the day and to bring one’s day to an end.
At first the quiet times may be quite barren or merely a retreat from exhaustion. One needs to get used to the stillness even after it has been achieved. The time may be used for taking stock, for examining one’s life direction, one’s plans, one’s relations, and the like. This is most profitable. It is like cleaning out the closets, or the desk drawers, and getting things in order.

Howard Thurman, Meditations of the Heart