When you sit on the toilet to take care of business, you may have noticed your nose starts to run. This bodily function has left people curious about why it happens in the first place. Here's the science behind it.
Anatomically, we have a shared membrane known as the "mucous membrane." It is a thin layer of tissue that lines different body cavities. When you poop, the muscles contracting to evacuate waste also push against your stomach and diaphragm, which in turn, places pressure on the veins near your posterior. That pressure will redirect fluid to the upper part of the body - towards the nose. It's called "vascular shunting," which explains why your nose runs when you poop.
Another factor at play is the role of the parasympathetic nervous system (PNS). The PNS is part of the autonomic nervous system, which is responsible for regulating bodily functions that we don't consciously control. When your PNS is triggered, it slows down your heart rate and relaxes the muscles in your digestive system to facilitate bowel movements and protect your bladder from emptying unnecessarily. The PNS also stimulates fluid secretion from cells within your nose, leading to a runny nose while you're sitting on the toilet.
1. Does everyone experience a runny nose when they poop?
Not necessarily. Some people may have a more active PNS or a differently-curved nasal cavity that facilitates an increase in fluid production, while others may not.
2. Does this occur with every bowel movement?
No, it's not guaranteed to occur with every bowel movement. It depends on your body and the bowel's force.
3. Is a runny nose when pooping anything to worry about?
It's normal and nothing to worry about!
Your nose running when you poop is only due to the anatomy and physiology of the body. So, the next time your nose runs while sitting on the toilet, you can rest assured that it is entirely normal and should not require any intervention or concern.
