Poor diet and lack of exercise are one of the important causes of constipation. People who exercise daily generally don't develop constipation because the colon responds to activity. Good muscle tone, in general, is important for regular bowel movements. The abdominal wall muscles and the diaphragm all play a crucial role in the process of defecation. If these muscles are weak, they will not be able to perform their job. Increasing exercise to improve constipation may be one of the most effective treatment methods in older people. Other causes include irritable bowel syndrome, pregnancy, laxative abuse, hormonal disturbances, loss of body salts and nerve damage.