As our abdominal muscles contract to move stool through the colon and rectum, this places increased pressure not only in the abdomen but throughout other areas of the body as well, including the surrounding nerves and blood vessels all the way up to the top of our head (via Healthline). As a result, a tear or two may leak out as we poop. It’s the same reason that some people may experience a runny nose when going #2 — and we all know that sometimes a heavy cry comes with a runny nose. Otherwise known as defecation rhinorrhea, the nerves that stimulate the muscle contractions needed to move waste through the colon are also connected to the nerves in our nasal passages (via Men’s Health). When prompted, this can lead to mucus secretions while pooping.
The vagus nerve is one such nerve that is thought to get triggered in particular. Facilitating communication between the gut and the brain, the vagus nerve relaxes the body by lowering heart rate and blood pressure as we poop. Once we’ve done our business, this can leave us feeling content and satisfied after the fact. Termed “poo-phoria,” some experts believe there may be a link between vagus nerve activation when pooping and the release of tears.