Your digestive system is remarkably efficient. In the space of a few hours it extracts nutrients from the foods you eat and drink, processes them into the bloodstream and prepares leftover material for disposal. That material passes through 20 or more feet of intestine before being stored temporarily in the colon, where water is removed. The residue is excreted through the bowels, normally within a day or two.
Some people — including many alternative therapists — say we should move our bowels one to three times a day to remain healthy, but this opinion is not backed by scientific studies.
Depending on your diet, your age, and your daily activity, regularity can mean anything from three bowel movements a day to one every three days. Nonetheless, the longer fecal material sits in the colon, the harder the stool becomes and the more difficult it is to pass. A normal stool should not be either unusually hard or soft, and you shouldn't have to strain unreasonably to pass it.
What Causes It?
Our busy, modern lifestyles may be responsible for most cases of constipation: not eating enough fiber or drinking enough water, not getting enough exercise, and not taking the time to respond to an unmistakable urge to defecate. Emotional and psychological problems can contribute to the problem. Persistent, chronic constipation may also be a symptom of more serious conditions, including irritable bowel syndrome, colorectal cancer, diabetes, Parkinson's disease, multiple sclerosis, an under active thyroid gland and depression.
Bowel habits tend to vary with age and circumstances. Bottle-fed babies, for example, tend to have firmer stools and more bouts of constipation than breast-fed babies. Some children become constipated when they start school or other activities because they are embarrassed to ask permission to use the toilet. Toddlers often become constipated during toilet training if he or she is unwilling or afraid to use the toilet. Being sensitive to pain, children may avoid the toilet if they have minor splits or tears in the anus from straining or other irritations.
Older people, especially those who are more sedentary, tend to develop constipation more often as well.
Medications can also cause constipation. They include narcotics, iron supplements and some medicines used to control blood pressure.
Medically updated by Tracy Shuman, MD, August 2005.
SOURCES: Family Practice Notebook. The Mayo Clinic.
