Heart Health

Why people faint: From common to very rare causes

By , Executive Editor, Harvard Heart Letter

About one in seven fainting episodes stems from heart‑related problems.

There’s one simple reason behind all fainting episodes — the brain isn’t getting enough blood. But there are many possible underlying causes, ranging from common, usually harmless issues to rare, potentially serious problems.

"Fainting always should be taken seriously, so be sure to get evaluated by a doctor if you faint, particularly if you have any history of heart problems," says Dr. Jeremy Ruskin, founder of the arrhythmia service at Harvard-affiliated Massachusetts General Hospital. But even people without any previous heart issues aren’t off the hook. Sometimes syncope (the medical term for fainting) is the first sign of a previously undetected heart condition, he says.

To continue reading this article, you must log in.

Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.

  • Research health conditions
  • Check your symptoms
  • Prepare for a doctor's visit or test
  • Find the best treatments and procedures for you
  • Explore options for better nutrition and exercise
Learn more about the many benefits and features of joining Harvard Health Online »

I'd like to receive access to Harvard Health Online for only $4.99 a month.

Sign Me Up

Already a member? Login ».

About the Author

photo of Julie Corliss

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio
View all posts by Julie Corliss

Disclaimer:

As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

You might also be interested in…

Better Balance: Simple exercises to improve stability and prevent falls

Discover how you can prevent falls by improving your balance and mobility. Better Balance: Simple exercises to improve stability and prevent falls gives you step-by-step instructions for easy, effective workouts that will improve posture, increase muscle strength and speed, sharpen reflexes, expand flexibility, and firm your core. You'll also get tips for fall-proofing your home.

Read More

Free Healthbeat Signup

Get the latest in health news delivered to your inbox!

Sign Up
Harvard Health Publishing Logo

Thanks for visiting. Don't miss your FREE gift.

The Best Diets for Cognitive Fitness, is yours absolutely FREE when you sign up to receive Health Alerts from Harvard Medical School

Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.

Harvard Health Publishing Logo

Health Alerts from Harvard Medical School

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss...from exercises to build a stronger core to advice on treating cataracts. PLUS, the latest news on medical advances and breakthroughs from Harvard Medical School experts.

BONUS! Sign up now and
get a FREE copy of the
Best Diets for Cognitive Fitness

Harvard Health Publishing Logo

Stay on top of latest health news from Harvard Medical School.

Plus, get a FREE copy of the Best Diets for Cognitive Fitness.