Acute constipation is not defined by the frequency of bowel movements. A normal bowel movement can be three times daily up to three times a week. One speaks of constipation, when the bowel movement is less frequent than three times a week and is difficult.
Further is constipation marked by hard feces, pain during bowel movement, tension in the lower abdomen, and a bloated belly.
Most of the time, decreased bowel movement frequency is the consequence of a low fiber nutrition, not enough liquid intake, or a lack of exercise. In the elderly, all factors are often coming together.
For chronic constipation (e.g., in case of constipation-dominant irritable bowel syndrome) laxatives should not be used longer than 14 days without medical supervision.