Eating disorders cause a number of medical complications. People with anorexia risk irreversible damage to the heart and brain. As starvation sets in, the body slows down certain functions to conserve energy. Breathing, pulse and blood pressure drop, and thyroid function slows. Nails and hair become brittle, and skin dries, yellows and grows a layer of soft hair called lanugo.
Dehydration causes constipation.
Reduced body fat leads to lowered body temperature and the inability to withstand cold. Anemia, swollen joints and reduced muscle mass are common to anorexia. People may also experience irregular heartbeat or heart failure. In women, anorexia often causes monthly menstrual cycles to stop. Afterward they may begin to lose calcium from their bones, increasing the risk of developing osteoporosis, a condition where bones become brittle and susceptible to breaking.