Recent Articles

Can a quick snooze help with energy and focus? The science behind power naps

Autism: The challenges and opportunities of an adult diagnosis

Hospice care: Overview of a compassionate approach to end-of-life care

Foot pain: A look at why your feet might hurt

Matcha: A look at possible health benefits

Wildfires: How to cope when smoke affects air quality and health

Forearm workouts: Strengthening grip for everyday function

Depression symptoms: Recognizing common and lesser-known symptoms

Medication side effects: What are your options?

Independent living with home care assistance: Balancing autonomy and support

Blacking Out, Fainting, or Loss of Consciousness

November 24, 2020

Welcome.

The two main reasons for blacking out are insufficient blood flow to the brain and abnormal electrical activity within the brain (a seizure).

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 ».

Share This Page

Print This Page

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.