Cut off from the body, one doesn't feel vulnerable. By identifying the self with the ego, one also gains the illusion of power. Since the will is the instrument of the ego, one truly believes "where there's a will, there's a way" or "one can do whatever one wills." This is true as long as the body has the energy to support the ego's directive. But all the willpower in the world is no help to a person who lacks the energy to implement the will. Healthy individuals do not operate in terms of willpower except in an emergency. Normal actions are motivated by feelings rather than by the will. One doesn't need willpower to do what one wants to do. There is no need to use the will when one has a strong desire. Desire itself is an energetic charge which activates an impulse leading to actions that are free and generally fulfilling. An impulse is a flowing force from the core of the body to the surface, where it motivates the musculature for action. The will, on the other hand, is a driving force that stems from the ego--the head--to act counter to the body's natural impulses. Thus, when one is afraid, the natural impulse is to run away from the threatening situation. However this may not always be the best action. One cannot always escape a danger by running. Confronting the threat may be the wiser course, but this is difficult to do when one is frightened and there is an impulse to run. In such situations mobilizing the will to counter the fear is a positive action.
--Alexander Lowen, MD, in Joy; The Surrender to the Body and to Life, page 81-82.