If nothing else has motivated lazy people to take up an active lifestyle before, perhaps the promise of a natural high will finally lure couch potatoes away from the subway and into the gym. For years, joggers and long-distance runners have reported feelings of euphoria that replace the pain of physical exertion caused by long periods of exercise. This euphoria gives them a feeling of effortless movement and has become a mythical goal known as "the zone." (Goldberg 1988) This speculation about the existence of the "runner's high" even inspired a legal controversy: in 1992, a jogger hit by a car filed a lawsuit against the driver. The driver's lawyer claimed that the jogger had acted recklessly while crossing the intersection where the accident occurred: the euphoria caused by a long period of physical exercise was responsible for giving the jogger a false sense of invincibility . (Shephard 1992) Whether or not this "runner's effect" physically exists is a topic of heated debate in the scientific community. Scientists have seen many cases where exercise has benefited people's mental health. For one thing, physical activity can significantly improve your self-esteem. Studies conducted on both children and clinically depressed patients show a clear improvement in self-esteem following aerobic and anaerobic training. (Biddle and Mutrie 1991) The exercise does this because it creates a situation in which the participant learns to master a task, thus gaining a feeling of control over their life. Therefore, exercise helps reverse depression, which according to the “learned helplessness” theory of depression, is caused by recurring cases in which patients have no sense of control over the outcome. The question is: is there a biochemical explanation for this? runner's high", or is it a purely psychological event (although one could also say that psychology is biochemical)? Exercise addiction, similar to substance addiction, seems to suggest that the euphoria of jogging might be biochemical. There have been reports of runners experiencing withdrawal symptoms when not exercising, such as nervousness, anxiety, and other unpleasant sensations Research shows that the body produces its own opiate-like peptides, called endorphins, and like morphine, they can cause addiction (Farrell). et al. 1982).Therefore, this is just one clue that suggests that these "endogenous morphine" compounds may be the chemicals that cause all of these psychological effects of exercise to pain and pleasure in the central nervous system.