Recent Blog Articles
Taking up adaptive sports
Cutting and self-harm: Why it happens and what to do
Discrimination at work is linked to high blood pressure
Pouring from an empty cup? Three ways to refill emotionally
Give praise to the elbow: A bending, twisting marvel
Sneezy and dopey? Seasonal allergies and your brain
The FDA relaxes restrictions on blood donation
Apps to accelerometers: Can technology improve mental health in older adults?
Swimming and skin: What to know if a child has eczema
A muscle-building obsession in boys: What to know and do
Blacking Out, Fainting, or Loss of Consciousness
Welcome.
The two main reasons for blacking out are insufficient blood flow to the brain and abnormal electrical activity within the brain (a seizure).
While both of these sound scary, in reality most episodes of blacking out are not related to life threatening health problems.
This guide is designed to provide insight into why you passed out. It is not a diagnostic tool or a substitute for evaluation by a health professional.
The questions are ones your doctor is likely to ask you. Your answers provide a path to better understanding of the common reasons for losing consciousness.
Certain situations demand emergency medical care.
Do any of the following apply to you?
- Chest pain or shortness of breath before or after you passed out
- Bloody or black stools
- Severe headache
- Recent blow to the head
- A heart condition
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
I'd like to receive access to Harvard Health Online for only $4.99 a month.
Sign Me UpAlready a member? Login ».
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.
Free Healthbeat Signup
Get the latest in health news delivered to your inbox!
