Fainting happens when you lose consciousness for a short amount of time because your brain isn’t getting enough oxygen.
The medical term for fainting is syncope, but it’s more commonly known as “passing out.” A fainting spell generally lasts from a few seconds to a few minutes.
Feeling lightheaded, dizzy, weak, or nauseous sometimes happens before you faint. Some people become aware that noises are fading away, or they describe the sensation as “blacking out” or “whiting out.”
Full recovery usually takes a few minutes. If there’s no underlying medical condition causing you to faint, you may not need any treatment.
Fainting isn’t usually a cause for concern, but it can sometimes be a symptom of a serious medical problem. If you have no previous history of fainting and you’ve fainted more than once in the past month, you should talk to your doctor.
Types of fainting
There are several types of syncope. Three common types include:
- Vasovagal syncope. Vasovagal syncope involves the vagus nerve. It can be triggered by emotional trauma, stress, the sight of blood, or standing for a long period of time.
- Carotid sinus syncope. This typically happens when the carotid artery in the neck is constricted, usually after turning your head to one side or wearing a collar that’s too tight.
- Situational syncope. This typically occurs due to straining while coughing, urinating, moving your bowels, or having gastrointestinal problems.
What causes fainting (syncope)?
Fainting (syncope) can be caused by an underlying medical condition or environmental triggers. Epilepsy is also caused by an emotional response to a very difficult situation. Severe pain, low blood sugar, or a change in blood volume can also cause syncope. If you have a drop in your blood pressure or heart rate, you may suddenly pass out.
Common causes of syncope:
- Low blood pressure or dilated blood vessels.
- Sudden changes in posture, such as standing too fast, which can collect blood in the feet or legs.
- Standing for a long time.
- Severe pain or fear
- Severe stress
Some people faint when they see blood. Syncope can also be triggered by multiple factors, such as if you are dehydrated or have low blood sugar. Together, even if you don’t faint from one or the other, those two things will make you faint.
Losing consciousness is the primary symptom of fainting. The following symptoms may occur leading up to a fainting episode:
- Feeling of heaviness in the legs
- Blurred or “tunnel” vision
- Feeling warm or hot
- Lightheadedness, dizziness, or a floating feeling
When a person faints, they may:
- Appear unusually pale
- Blood pressure and a weak pulse
If a person with an underlying health condition, they will require treatment. This will help prevent future fainting episodes. Often, however, no further treatment is necessary.
To help prevent further fainting episodes, people should try to avoid triggers, such as dehydration, and spending a lot of time in hot environments.
If the sight or thought of injections or blood make a person feel faint, they should tell their doctor or nurse before undergoing a medical procedure that may involve this. The doctor or nurse can then make sure that the individual is in a safe position, such as lying down, before starting the procedure.
People mainly use beta-blockers to treat high blood pressure. However, these drugs may also help if neurocardiogenic syncope interferes with a person’s quality of life.
However, some adverse effects of beta-blockers include fatigue, cold hands and feet, a slow heartbeat and pulse, nausea, and diarrhoea.
What to do when someone faints
When someone near you faints, you can encourage blood flow to their head by raising their feet above the level of their heart.
Alternatively, you can have them sit with their head between their knees.
Loosen tight collars, belts, and other restrictive clothing. Keep the person lying down or sitting for at least 10 to 15 minutes. A cool, quiet place is best. A cool drink of water may also help.
How to prevent fainting
If you have a history of fainting, try to learn what’s causing you to faint so you can avoid those triggers.
Always get up slowly from a sitting or lying-down position. If you tend to feel faint at the sight of blood when getting your blood drawn or during other medical procedures, tell your doctor. They can take certain precautions to prevent you from fainting. Feeling lightheaded and weak and having the sensation of spinning are warning signs of fainting. If you notice any of these signs, sit and put your head between your knees to help get blood to your brain.
You could also lie down to avoid injury due to falling. Don’t stand up until you feel better.