The most significant dangers of extreme exercise are overuse syndromes such as stress fractures, heart arrhythmias where metabolism has been altered, and amenorrhea.
Stress fractures are micro-fractures of the bone, typically in weight-bearing areas such as feet and lower legs. Stress fractures develop from repetitive, high-impact, weight-bearing aerobic activity. Eating disorder patients, because they often have bone loss from osteopenia or osteoporosis, are particularly susceptible to stress fractures. Often stress fractures do not show up on x-rays but require a bone scan or MRI. Stress fractures limit a woman's ability to exercise, lead to pain during exercise and long-term pain if not allowed to heal, and increase the risk of major bone fractures which may ultimately promote curvature of the spine. Treatment includes resting the extremity, use of assistive devices if it is painful to walk, and avoidance of the repetitive activity that caused the fracture. In eating disorder patients with malnutrition, treatment also includes calcium and vitamin D supplementation, weight restoration, and resumption of normal menstruation.
