Abstract

Vigorous exercise is associated with a sensation of well-being, and this subjective state has been objectively quantified with psychometric, cardiovascular, and neurophysiological data. Reductions in state anxiety have been demonstrated to follow acute physical activity, and this response persists for 2-5 h. Chronic physical activity has been associated with reductions in anxiety and depression, as well as increases in self-esteem. This research has been limited to designs of a correlational nature, and the issue of causality vs mere association has not been resolved or addressed. Three hypotheses based upon distraction, monoamine metabolism, and endorphin release are discussed in this paper. Investigators have traditionally attempted to illustrate the mechanism involved in improved mood following exercise by testing one of these or related hypotheses, but it is likely that advances will not be made in this area until these hypotheses are examined in a multiple or synergistic manner. It is concluded that each of the hypotheses reviewed remains tenable.