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 about 20 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.
Depending on your diet, age, and daily activity, regularity can mean anything from three bowel movements a day to three each week.
If 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.
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. Kids can also become constipated from consuming certain foods, such as dairy products.
Older people, especially those who are more sedentary, tend to develop constipation more often.