Wikipedia
Anorexia athletica, (sports anorexia) also referred to as hypergymnasia is an eating disorder characterized by excessive and compulsive exercise. An athlete suffering from sports anorexia tends to over exercise to give themselves a sense of having control over their body. Most often, people with the disorder tend to feel they have no control over their lives other than their control of food and exercise. In actuality, they have no control; they cannot stop exercising or regulating food intake without feeling guilty. Generally, once the activity is started, it is difficult to stop because the person is seen as being addicted to the method adopted.
Anorexia athletica is used to refer to "a disorder for athletes who engage in at least one unhealthy method of weight control". Unlike anorexia nervosa, anorexia athletica does not have as much to do with body image as it does with performance. Athletes usually begin by eating more 'healthy' foods, as well as increasing their training, but when people feel like that is not enough and start working out excessively and cutting back their caloric intake until it becomes a psychological disorder.
Hypergymnasia and anorexia athletica are not recognized as mental disorders in any of the medical manuals, such as the ICD-10 or the DSM-IV, nor is it part of the proposed revision of this manual, the DSM-5. If this was the case, there would be a 10-15% increase in mental disorders in sports. A study at the Anorexia Centre at Huddinge Hospital in Stockholm, Sweden showed that sports anorexia can result in mental disorders. The anxiety, stress, and pressure people with sports anorexia put on themselves (as well as the pressure parents and coaches can put on the athlete) can cause mental disorders.