When to go to the Doctor for Fainting

Woman leaning hand on wall and holding head.jpg

Fainting is one way your body communicates something’s out of whack. Scientifically known as syncope, and unscientifically known as passing out, fainting happens when the brain loses consciousness for a moment. It’s triggered by various factors that can disrupt the delicate balance between proper blood flow, oxygen and our nervous systems. Stephen Pallone, MD, UnityPoint Health, explains why someone might faint and what to do when it happens.

What Causes Fainting?

According to the American Academy of Family Physicians, about 40% of the U.S. population experiences a fainting episode in their lifetime. There are three big categories for why people faint, including:

Other reasons for fainting include:

  • Heat
  • Hearing bad news
  • Standing up too quickly
  • Dehydration
  • Scary sights
  • Gross smells
  • Feeling hungry
  • Straining while having a bowel movement

Dr. Pallone says people who faint without any major medical issues usually have a history of it.

What Happens When You Faint?

Neurological (Nervous System) Issues

When people think of fainting, Dr. Pallone says they’re likely thinking of the most common form, which is neurological and makes up about 45% of cases. Picture the last movie you watched where someone received unsettling news—the back of their hand hits their forehead, eyes close and before you know it, their body hits the floor.

“The parasympathetic nervous system, which helps us feel calm and safe, gets overstimulated because of a surprising event, like a blood draw or something that makes people woozy. That causes your heart rate to slow down and blood vessels to dilate, which decreases blood flow and oxygen to the brain, so, you pass out,” he says.

“While startling, some people just have that kind of reaction, and it’s not a big deal. We know there’s usually a trigger for it.”

He adds, “However, fainting can still be a big deal and should be taken seriously.”

Heart Problems

Nearly 20% of fainting episodes are due to cardiac issues. When it comes to heart problems, there are a few conditions that can lead to fainting.

  • Irregular heartbeats: These are called arrhythmias. Certain types can disrupt blood flow to the brain and result in fainting.
  • Heart attacks: Fainting during a heart attack can happen if the heart can’t pump blood effectively, leading to a decrease in blood flow to the brain. Not everyone who has a heart attack will faint.

Low Blood Pressure

Dr. Pallone says the most common cause of fainting in people with low blood pressure is taking too much of their medication—even if they’ve been taking it for years.

“When you’re stable but getting older, other medicines might be added to your regimen and slow down your metabolism. This can cause low blood pressure and lead to fainting,” he says.

Blood pressure medications, such as alpha-blockers, beta-blockers or certain antihypertensive drugs, work by relaxing blood vessels, reducing heart rate or decreasing fluid volume. When taken in large amounts, or combined inappropriately, they can cause blood pressure to drop too low, which, as Dr. Pallone explains, can cause fainting.

POTS (Postural Orthostatic Tachycardia Syndrome)

POTS is a condition that can happen when people change positions, particularly, when they stand up. Blood isn’t effectively pumped against gravity up to the brain because of a dysregulated autonomic nervous system.

“The reduced blood flow to the brain can cause fainting. During an episode caused by POTS, the body overcompensates and makes symptoms more intense. Sometimes, heart rate can get up to 100 beats per minute until the body regulates itself,” Dr. Pallone says.

How Long Does Fainting Last?

A fainting episode can last anywhere from a few seconds to a few minutes. When you wake up, your body’s circulation goes back to doing its job, and you’re back to normal.

“What distinguishes fainting from other episodes of losing consciousness is the rapid return to normal mental functioning,” Dr. Pallone says.

What Does Fainting Feel Like?

Dr. Pallone says fainting is sudden.

“Sometimes, the person who faints will experience lightheadedness and say something about it. Other times, they just collapse to the ground.”

Additional fainting symptoms include:

What to do When Someone Faints

Dr. Pallone says the best thing to do when someone faints is to assess the person to see if they’re responsive—similar to what you’d do before giving CPR.

“It's always a good idea to see if they respond by checking their pulse, circulation and breathing. If they have a beating heart, and they’re breathing, watch them for a bit to see if they recover. If they don’t recover within 15 – 30 seconds, call 911 right away,” he says.

How to Prevent Fainting

If you have a history of fainting, know what triggers an episode and try to avoid it.

“A patient fainting because of a blood draw is fairly common in health care, and because blood draws are necessary, they’re not avoidable. However, giving yourself time to mentally prepare and staying hydrated is sometimes helpful,” he says.

For more serious cases of fainting, Dr. Pallone says they’re not always preventable but following a healthy lifestyle is recommended.

Can You Die from Fainting?

A person’s chances of dying from fainting are extremely low—less than 1% in the first 10 days and about 1.6% within in 30 days. Around one third of fainting cases have no apparent underlying health condition to explain them either.

“The likelihood of an episode being life threatening is low, but it shouldn’t be written off as something you don’t need to get checked out,” Dr. Pallone says.

When to See Your Doctor

Always contact your doctor for a check-up after your first fainting episode. They’ll usually do a blood test to look at electrolytes and kidney function as well as perform an electrocardiogram and blood pressure check. Based on your medical history, your doctor may choose to order additional tests or imaging, too.