Exercise addiction is similar to many other types of addictions. Granted exercise is good for you, but in moderation.
Exercise addiction can cause people to over-train on a constant basis while never giving the body time to recuperate which can deny the addict the results they crave. As with other addictions, there are multiple reasons why people become addicted. Some do it for weight loss or weight management. Becoming addicted for weight loss is often associated with anorexia and bulimia.
Anorexics and bulimics over train to lose weight while being malnourished which in itself can cause extra health risks. On the other side of spectrum there is “Bigorexia”, a term coined specifically for bodybuilders who are never satisfied with their size; regardless of how “big” they get, it is never enough.
Below are some of the articles I found interesting on this topic.