

Sarah Giles, The Canadian Press





TORONTO -- Sitting on the toilet in her Washington, D.C., apartment dripping with sweat and feeling like she was about to pass out, Ami Sanchez thought, "No! I can't die on the can!" as she dialled 911.

Sanchez, a physically active and healthy professional in her mid-30s, had woken that night just over a year ago with terrible stomach pain and an urgent need to poop. But nothing was produced - she just felt faint. Thankfully, before she had time to collapse on the hard bathroom floor, the paramedics arrived.

By the time Sanchez got to the emergency room, she was surprised to find that she felt perfectly fine. In the hospital, doctors performed a physical exam, a blood test and an electrocardiogram, all of which were normal.

Doctors told Sanchez pain had triggered her "vasovagal response" and mentioned they often see people who faint after they had been constipated and straining. They left her with the following words of wisdom: "Don't push so hard next time."

"Defecation syncope" is the official term for fainting while trying for No. 2. In Canada, syncope accounts for approximately one per cent of all emergency room visits, but it is not well established how many of these episodes can be attributed to defecation. Some patients will not admit to it, and some doctors do not ask.

Dr. Robert Sheldon, a cardiologist at the University of Calgary and syncope researcher, says 2 to 3 per cent of the syncope cases he sees in his practice are related to defecation.

Fainting on the toilet may happen for a number of reasons. If a person is constipated, they may have the urge to take a deep breath, then push and strain. But straining lowers the volume of blood returning to the heart, which decreases the amount of blood leaving it.

Special pressure receptors in the blood vessels in the neck register the increased pressure from straining and trigger a slowing of the heart rate to decrease in blood pressure, leading people to faint. This vasovagal reflex can cause people who are dehydrated or have low blood pressure to pass out in many different circumstances, not just on the toilet.

Though it may be scary to pass out while on the toilet, overstraining and pain, rather than underlying heart disease, are by far the most common reasons for fainting on the toilet according to Dr. Chris Simpson, a syncope expert and acting dean of health sciences at Queen's University.

Simpson says that he has never uncovered a potentially life-threatening, hidden condition in someone who complained of defecation syncope.

A 2017 study in the Journal of Pacing and Clinical Electrophysiology followed almost 300 people who passed out after a vasovagal episode or a situational stress. After two years, no deaths were reported among subjects, although approximately 40 per cent of the participants did faint again.

Those who require particular attention when they faint, however, are those who pass out during exercise, extreme emotion, after being startled, or have a "family history of sudden death at a young age for no apparent cause," says Simpson. That may be a sign of underlying heart issues such as aortic stenosis, a narrowing of the aortic valve, and obstructive hypertrophic cardiomyopathy, a disease where the heart becomes abnormally thickened and has difficulty pumping properly.

While defecation syncope may not be lethal, the bathroom is not the safest place to pass out. Fainting on the toilet can lead to injury. Sanchez says she is speaking up because she wants others to learn from her experience. "We can prevent people from getting hurt unnecessarily," she says.

Simpson has recommendations for avoiding fainting in the john: If people feel sweaty, cold, or clammy, he suggests "getting yourself flat quickly" to avoid injury and full-blown fainting. He also advises drinking plenty of water and, for people with low or normal blood pressure, adding a little more salt to the diet.

Dr. Sarah Giles is a fellow in global journalism at the University of Toronto.