How to Tell if Your Bowel Movements Are Causing Vasovagal Syncope

Feeling faint? Your body might be reacting to a trigger

Woman in bathroom with stomachace
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Do you ever experience symptoms of sweating and feeling like you are going to pass out during a bowel movement? You may have one nerve in your body that is the culprit, your vagus nerve.

A trigger like a straining during a bowel movement or the sight of blood might just be enough for your vagus nerve, or your body's vasovagal response, to send you into a fainting spell. The medical term for this fainting spell is called vasovagal syncope.

More About the Vasovagal Response

The vasovagal response is an automatic reflex stimulating your vagus nerve that can affect your central and peripheral nervous system, as well as your cardiovascular system.

The vagus nerve can send a message to the brain that causes a sudden drop in blood pressure and your heart rate. The word "vasovagal" describes the two parts of your body that cause your body's response, "vaso" involving your blood vessels and "vagal" referring to your vagus nerve.

If the vagus nerve is stimulated suddenly, several body changes may occur, giving you an early warning sign of a potential fainting spell.

Symptoms of Vagus Nerve Stimulation
Dizziness, feeling faint or light-headed
Feeling suddenly warm, sweaty, or having your skin feel cold and clammy
Blurry vision or tunnel vision (blackness in the periphery of your vision)
Feeling nauseous
A ringing in your ears
Turning pale
Temporary loss of consciousness through a fainting spell

Why Does This Happen?

The vasovagal response or reflex is not necessarily abnormal; the neural pathways involved in the vasovagal response are most likely present in all people and scientists believe this reflex evolutionarily developed as humans became upright. The difference now for some people is that some are more susceptible to having the reflex triggered.

In some cases, there may be an underlying medical condition, such as a neurological condition that can cause a person to experience these symptoms. Another possibility is that there is some underlying heart problem. Often, no specific cause can be found.

Because vasovagal symptoms can sometimes be attributed to an underlying disease, bring any symptoms to the attention of your doctor for proper evaluation.

What To Do If This Happens to You

If your doctor does not find any medical diagnosis to explain your symptoms, you may benefit from following some basic self-care recommendations. For syncope, people are advised to do their best to avoid things that trigger the reflex.

Triggers can include standing up quickly or standing for too long, not getting adequate sleep, dehydration, straining during bowel movements, irritable bowel syndrome, having your blood drawn, the sight of blood or acute emotional stress.

Tips to Control Triggers

If a bowel movement has caused you to pass out, while on the toilet, you can cross your legs, keep your the muscles tight, and lower your head toward the floor to help to stabilize your blood pressure. 

If stress is a trigger, keep yourself as calm as possible. Although such episodes can be scary, you can use calming self-talk and mind-over-body practice to help get yourself through the stress period and reduce panic.

Remind yourself that your symptoms will pass. You can find reassurance in the fact that your doctor has checked you out and ruled out any more serious causes of your symptoms. 

You Are Not Alone

Vasovagal syncope during bowel movements is one of the most common manifestations of the vagus response. The following accounts are from three separate people who have experienced a vasovagal response triggered by bowel issues.

"The bad part is that, with the rectal pain, I will begin to have a vagus response: my throat will tighten, I will begin salivating, get hot and sweaty. Then spasms will start in my stomach and I will begin rhythmic heaving with acid reflux. There isn't anything in my stomach, so there is not much to vomit, but on occasions, I will bring up the water or the coffee and bile, I suppose. The spasms are quite violent and when the episode is over, I am completely wasted. Sometimes this sequence happens once, but I have had up to three experiences in a morning. It makes it impossible to leave the house some days!"
"I too have vasovagal response during painful cramping IBS attacks. During extreme attacks I always have tingling, profuse sweating (drenching), light-headedness and get close to passing out. I have never actually passed out however. These symptoms make coping with IBS symptoms a lot more difficult because I am unable to think straight and the pain is beyond belief."
"I have suffered from vasovagal (reflex) since I am a child. It wasn't until I was an adult that it was diagnosed. I do know my triggers and have become more aware of how to avoid passing out. However, in the last few years I also suffer from IBS....I have had three serious occasions where the IBS attack was so severe that I had a vasovagal attack. Each time I was extremely close to passing out.....dizzy, blurred vision, headache, nausea, and a drenching sweat."


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