A bowel movement or defecation is the passing of stool through the anus. Normally, it occurs anywhere between one to two times a day to three times or more a week. If it occurs more often or less frequently than the norm, then it is often classified as diarrhea or constipation respectively. However, the definition of diarrhea as having more than 3 bowel movements in a day can be misleading. It does not clearly state the nature and quantity of the bowel movement which are characteristic of a disturbance in the processes of gastrointestinal absorption and defecation. Diarrhea is the passing of more than 200 g (solid) / 200 ml (liquid) of stool in three or more bowel movements within a 24 hour period. The stool is not of a normal consistency, usually watery, and often associated with various other symptoms like urgency, flatulence, abdominal cramping/pain and bowel incontinence to some degree.

There are however cases of frequent bowel movements that cannot fit into the classical presentation of diarrhea. While there is no clear clinical definition for this phenomenon, patients will report a change in bowel habit with an increase in the number of bowel movements in a day. Usually there is little to no difference in the consistency or color of the stool – it is still firm but not hard and light to dark brown. In most cases, it is not a sign of any disease but rather an indication of a change in dietary habits, routine, stress levels or even physical exercise. It may also be associated with the use of stimulants like nicotine (tobacco) or caffeine (coffee/tea), especially if there is excessive use within a short period of time.

However, frequent bowel movements may be the first sign of various diseases that causes diarrhea. It may precede full-blown diarrhea, especially in chronic disease, and should be investigated if it is persistent. A temporary change in bowel movement is not uncommon and should not be immediately attributed to any disease process.

Causes
If you're having bowel movements more often than usual, chances are you've made some change in your lifestyle. You may, for example, be:
Eating more fruits, vegetables and whole grains, which increases fiber intake
Getting regular exercise or increasing your exercise
Drinking more water
More-frequent bowel movements could also be related to a mild, self-limiting illness that will take care of itself. If there are no other signs or symptoms, you're probably in good health.
Suffering from Proctitis