Passing over some reasons you may be passing out

Years ago, a fluke happened.

I finished running on my treadmill. Feeling good, I decided to walk Rosie, my old German shepherd mix. At the end of the block, we ran into our neighbor Isla and her black Lab, Moose. We got talking – animatedly. After a while, I began to feel tsunamis of nausea and stomach pain.

Next thing I knew, I was staring at the great blue sky and wet dog noses.

I turned my head and saw another curiosity – in the distance, Isla was weaving and waving frantically in the middle of the street.

My first thought: She’s going to get herself killed.

That was the first time I’d ever passed out. According to Isla, I collapsed. She was quick to catch me, laid me down on the grass. While the dogs sniffed me aggressively for signs of life, she ran up and down the street looking for help.

“I’ve never seen anybody collapse like that,” she said. “It scared the hell out of me.”  

Passing out, fainting, or syncope as we call it in medicine, is common. Up to 40% of us will experience an episode sometime in our life.

The mechanism is simple: a drop in blood flow to the brain. We lose consciousness briefly. And it’s scary.

In healthy people, benign conditions cause most syncope. The episode averages 17 seconds. If it lasts more than a few minutes, doctors begin to worry about other causes, like seizures. It’s usually caused by some nerve reflex reaction that drops blood pressure. The triggers can be pain, heat, emotional stress, getting blood drawn, dehydration, drinking alcohol, prolonged sitting or standing or movements like urinating, defecating, violent coughing.

So you ask: why does our body, out of the blue, decide to drop blood pressure instead of raising it when we’re stressed? That’s anybody’s guess. Doctors can usually accurately diagnose these benign conditions by a good history and physical.

When do you worry?

About 10% of syncope are caused by dangerous heart conditions: abnormal rhythms and structures. There’s usually a history of known heart diseases like irregular heartbeat, heart failure, enlarged heart, etc.

The following presentations are alarming: 1. Passing out suddenly, that is, without any warning or preceding symptoms; 2. Passing out during exertion; 3. Heart palpitation (a sensation of fast or irregular heartbeats) before syncope; 4. A family history of unexplained sudden death before the age of 35. There are more, but these are most common.   

Syncope is not entirely benign. About 30% result in significant injury. My husband passed out after urinating at the Westlake Recreational Center (the fancy name for this benign condition is micturition syncope). His head hit something hard. A scalp wound bleeds more because of its rich vasculature. When the EMS arrived, the locker room apparently looked like a blood-splattered crime scene.

My syncope was likely a combination of dehydration and emotional excitement. Thanks to Isla and the dogs, I didn’t have a single bruise or sore muscle. I woke up feeling calm and peaceful. But poor Isla: “I’ve never been so scared in my life.”