Defecation Syncope: Why You May Feel Weak Or Black Out While Defecating

Published by Dr Gigi on

Have you ever blacked out or felt like you were going to pass out after defecating? That is called defecation syncope; it is a temporary loss of consciousness (blacking out) or weakness that happens during or immediately after defecation.  Syncope is known as sudden, temporary loss of consciousness, which may also be accompanied by failure to maintain your normal posture.  It mimics some types of seizures, coma, or other forms of conditions characterized by loss of consciousness.

It may occur at any time of the day. It may occur only once or many times throughout the life of an affected individual. In some cases, it may be associated with other conditions such as  cardiovascular disease. On many occasions, it is preceded by abdominal symptoms such as cramps, intense urge to defecate alongside diarrhea, or nausea and vomiting. These symptoms are the only warning signs in some individuals.

Who is likely to be affected?

It is more common in older people especially elderly women.1 About 65-78% of individuals experiencing DS are elderly women.2

Individuals with cardiovascular diseases or autonomic dysfunction (dysfunction of the nerves) are at increased risk of DS.

In many cases the cause is unknown.


The mechanism by which DS occurs is not clearly understood. It is believed that straining at defecation sets in motion events that precipitate DS. During normal defecation there is an interplay between voluntary straining and involuntary activities of nerves and muscles of the anus. When one strains, the throat ( glottis)is closed off, preventing breathing and at the same time, pressure in the chest and abdomen increase compressing the heart. These events result in reduced heart rate, low blood volume pumped by the heart and lower blood pressure. Normally, the body is able to quickly detect the sudden fall in blood pressure and correct it. However, in some cases, especially with prolonged straining, the resultant reduction in blood pressure, means less blood flow to the brain, which may leading to loss of consciousness or light headedness.

Role of defecation position.

Symptoms of DS are more intense, take longer and more likely to recur when defecating seated on a toilet bowl or into a bed pan compared to the squatting position.3

Squatting to poop may help prevent fainting while defecating.3 Traditionally, humans squatted to relieve themselves, but with modern inventions, this method was ditched for the toilet bowl. When an individual squats, there is less straining to defecate, blood flow back to the heart increases, further increasing heart rate and blood supply to the brain. This is the opposite of the precipitating events leading to DS.3

Can DS lead to death?

It is believed that excessive and prolonged straining necessary to aid defecation in the seated position especially in elderly  patients, can lead to death due to heart related complications.

In healthy individuals, the heart and circulatory system quickly recover from effects of straining and prevent death from DS.

Squatting reduces the risk of DS. Therefore, individuals with heart disease will benefit from squatting while pooping and avoiding the use of bedpan if possible.3

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Dr Gigi

Dr Gigi is a medical doctor, an avid researcher and founder of HeLP. She is a healthy life enthusiast. She is passionate about finding better and healthier alternatives and helping to improve people's quality of life. She started Healthy Life Pantry (HeLP) with aims to provide simplified research based and proven health information, delivered by seasoned health care professionals.

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