The digestive system

Digestive phenomena

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Constipation refers to stools which are generally hard, less plentiful and less frequent than normal (less than 3 stools per week).

Some causes:

  • Bad eating habits
  • Lack of physical exercise
  • Taking certain medication
  • Strong emotional responses
  • Psychological factors

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In contrast to diarrhoea, constipation corresponds to hard stools that are less frequent and less voluminous than usual. It leads to a delay or even problems with expelling stools. The frequency of evacuation of stools varies from one person to another, but it roughly ranges from three times per day to three times per week. Constipation occurs when the frequency is less than three times per week.


Among some of the causes of constipation, the first is poor eating habits that produce stools with a low water or fibre content. Not getting enough exercise or taking certain medication (such as anti-inflammatories), may slow down peristalsis in the digestive tract. Muscle contractions are not able to move food residues fast enough, causing stools to stay in the colon too long. This is where the body reabsorbs a lot of water so, the stools then become hard and difficult to pass.

As with diarrhoea, intense emotions such as anxiety or stress can also trigger constipation. Sometimes, the anal sphincter (which is the muscle of the anus) contracts instead of relaxing. In doing so, it prevents stools from being expelled and they accumulate in the rectum instead. The reasons are often related to psychological factors. Diarrhoea phobia is the fear of having urgent diarrhoea attacks and not being able to hold things in before finding a toilet. This fear can delay and even stop defaecation.

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