Why people faint

  • 1 Low blood pressure

    A person might experience a drop in blood pressure when they stand up which reduces circulation to the brain causing the person to lose consciousness. 

  • 2 Heart beat slowing down

    A type of fainting called vasovagal syncope causes the heart beat to slow down or pause for a few seconds causing the person to lose consciousness. This could be due to seeing an unpleasant sight, sudden pain, anxiety, fear, extreme emotional stress or heat. 

  • 3 Due to hyperventilation

    Fainting can occur due to hyperventilation (inhaling too much oxygen and exhaling too much carbon dioxide quickly). This usually happens when a person is panicking. 

  • 4 Due to dehydration

    A person could faint as a result of their body being dehydrated. 

  • 5 Due to alcohol consumption

    Fainting can happen when a person consumes high amounts of alcohol. 

  • 6 Heart problems

    The kind of fainting related to heart problems is called cardiac syncope. People of older age are more at risk of this kind than younger people. This could be due to irregular heart rhythm, for example. 

  • 7 Due to inflammation and pain of a nerve

    Fainting might happen due to inflammation and pain of a certain nerve found in the mouth. 

  • 8 Due to intense coughing

    Fainting may occur after an intense coughing session. This type of fainting is called cough syncope. 

  • 9 Due to stretching

    Fainting could happen when a person is stretching their arms and neck as a result of stimulating a certain nerve. This type of fainting is called stretch syncope. 

  • 10 Fainting during urination

    A person could experience fainting after or during urination as a result of stimulating a specific nerve. This is called micturition syncope.

  • 11 Due to seizures

    A person may faint when they experience a seizure which is accompanied by a number of other symptoms such as feeling of confusion afterward, muscle spasms, drooling or frothing and teeth clenching. 

  • 12 Due to a heart attack

    A person might experience fainting when they are having a heart attack. 

  • 13 Low blood sugar

    A person with low blood sugar (hypoglycemia) may experience loss of consciousness. People with diabetes are more likely to experience this type of fainting. 

  • 14 Due to a medical allergic reaction

    Some people may experience fainting as a result of being allergic to a certain medication. Other symptoms which might accompany loss of consciousness are rash, fever and trouble breathing. 

  • 15 Due to food allergy

    People who have certain food allergies may experience fainting in extreme situations. Fainting is a severe symptom of food allergy that does not always happen. 

  • 16 Due to an eating disorder

    People with eating disorders such as anorexia nervosa may experience fainting as a result of severe weight loss and their body's deprivation of food. 

  • 17 Due to a blood clot

    Fainting can happen as a result of a pulmonary embolism (blood clot in the lung). 

  • 18 Reflex anoxic seizures

    Reflex anoxic seizures (RAS) are more common among young children where their hearts involuntarily slow down and may even stop beating for 5-30 seconds. This type of fainting is accompanied with rolled back eyes, crawled fingers and body jerks.