Fainting is when you pass out for a short time. It’s not usually a sign of something serious, but if it happens regularly you should see a GP.
Causes of fainting
There are many reasons why someone might faint.
- standing up too quickly – this could be a sign of low blood pressure
- not eating or drinking enough
- being too hot
- being very upset, angry or in severe pain
- heart problems
- taking drugs or drinking too much alcohol
Symptoms of fainting
Fainting usually happens suddenly. Symptoms can include:
- cold skin and sweating
- slurred speech
- feeling sick
- changes to your vision
Non-urgent advice: See a GP if:
- you have fainted and do not know the cause
- you have recently fainted more than once
You must tell the Driver and Vehicle Licensing Agency (DVLA) if you’re fainting regularly as it could affect your ability to drive.
Things you can do to prevent fainting
If you feel like you’re about to faint, try to:
- lie down with your legs raised – if you cannot do this, then sit with your head lowered between your knees
- drink some water
- eat something
- take some deep breaths
If you see someone faint
If you’re with someone who has fainted, try to keep calm.
If you can, lay them on their back and raise their legs.
Usually, the person who has fainted will wake up within 20 seconds.
Immediate action required: Call 999 if:
Someone faints and they:
- cannot be woken up after 1 minute
- have severely hurt themselves from a fall
- are shaking or jerking because of a seizure or fit
Page last reviewed: 02 January 2020
Next review due: 02 January 2023
Fainting is pretty common in teens. The good news is that most of the time it’s not a sign of something serious.
What Is Fainting?
Fainting is a temporary loss of consciousness. It happens when there isn’t enough blood going to the brain because of a drop in blood pressure.
Why Do People Faint?
Blood pressure can drop from dehydration, a quick change in position, standing or sitting still for a long period, or a sudden fear of something (such as the sight of blood).
Here are some of the common reasons for fainting:
Physical triggers. Getting too hot or being in a crowded, poorly ventilated setting are common causes of fainting. Sometimes just standing for a very long time or getting up too fast after sitting or lying down can cause someone to faint.
Emotional stress. Emotions like fright, pain, anxiety, or shock can cause to drop. This is the reason why people faint when something frightens or horrifies them, like the sight of blood.
Hyperventilation. A person who is hyperventilating is taking fast breaths. Carbon dioxide (CO2) levels in the blood falls, causing blood vessels to narrow. Blood flow to the brain decreases, making a person faint.
Medical conditions. Conditions such as heart problems, anemia, low blood sugar, or postural orthostatic tachycardia syndrome (POTS) can cause fainting.
Pregnancy. During pregnancy, the body undergoes a lot of changes, including changes in the circulatory system. These may cause a woman to faint. And as the uterus grows, it can press on and partially block blood flow through large blood vessels, which can decrease blood supply to the brain.
What Are the Warning Signs of Fainting?
Someone who is about to faint might have:
- vision changes
- fast or irregular heartbeat
- nausea and/or vomiting
Can Fainting Be Prevented?
If you think you’re going to faint, you can try to stop it by taking these steps:
- If possible, lie down. This can help prevent a fainting episode, as it lets blood get to the brain. Be sure to stand up again slowly when you feel better — move to a sitting position for several minutes first, then to standing.
- Sit down with your head lowered forward between your knees. This will also help blood get to the brain, though it’s not as good as lying down. When you feel better, move slowly into an upright seated position, then stand.
- Don’t let yourself get dehydrated. Drink enough liquids throughout the day. Drink plenty of fluids before, during, and after exercise and in hot weather.
- Keep blood circulating. If you have to stand or sit for a long time, take breaks often and move around. Regularly tense your leg muscles or cross your legs to help improve blood flow.
- Avoid overheated, cramped, or stuffy environments, whenever possible.
When Should I Call the Doctor?
If you’ve only fainted once, it was brief, and the reasons why are obvious (like being in a hot, crowded setting), then there’s usually no need to worry about it. But if you have a medical condition or are taking prescription medicines, it’s a good idea to call your doctor.
Call the doctor or get medical care if you:
- hurt yourself when you fainted (for example, if you banged your head really hard)
- have chest pain, palpitations (fast or irregular heartbeats), or shortness of breath
- had a
- fainted during exercise or other physical activity
- have fainted more than once
The doctor will ask a few questions, do an exam, and might order some tests, such as:
- an EKG (a type of test for heart problems)
- a blood sugar test
- a blood test to check for anemia
How Can I Help Someone Who Faints?
If you’re with someone who has fainted, try to help the person lies down. Don’t move someone who might be injured from falling (that can make things worse). Instead, loosen any tight clothing — such as belts, collars, or ties. Propping the person’s feet and lower legs up on a backpack or jacket also can help blood flow to the brain.
Someone who has fainted will usually recover quickly. Because it’s normal to feel a bit weak after fainting, be sure the person stays lying down for a bit. Getting up too soon may bring on another fainting spell.
Call 911 if someone who has fainted:
- does not regain consciousness after a few minutes
- passed out while exercising
- is having chest pain, trouble breathing, or a seizure
Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately
healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.
If you don’t know whether someone is fainting or is having a serious incident like a cardiac arrest, follow DRSABCD.
What is fainting?
Fainting, also called syncope, is a period of temporary loss of consciousness that happens when the blood flow to the brain is reduced.
When should I see a doctor?
People normally recover quickly after fainting. Fainting can be the sign of a medical condition, like a heart or brain disorder. It’s always worth checking with your doctor, especially if you haven’t fainted before.
You should see a doctor if you:
- have fainted and do not know the cause
- have recently fainted more than once
When should I call an ambulance?
You should call an ambulance if you:
- have injured yourself — especially if you hit your head
- are pregnant
- have diabetes or heart disease, or if you had chest pains or palpitations before you fainted
- have lost bladder or bowel control
- took longer than a few minutes to regain consciousness
What are the symptoms of fainting?
Before fainting, it’s common to experience some of the following:
- changes to your breathing, such as breathing faster and deeply
- altered vision, such as blurring and seeing spots or lights
CHECK YOUR SYMPTOMS — Use the collapse and fainting Symptom Checker and find out if you need to seek medical help.
What causes fainting?
There are a number of things that can cause you to faint, including:
- changes to your blood pressure, especially when you stand up
- some medicines
- a nervous system problem
- a heart problem
- a seizure
In some people, fainting is caused by a temporary glitch in the autonomic nervous system that regulates your heart rate and blood pressure. This can be triggered by:
- experiencing high levels of pain
- exposure to sights you find unpleasant, such as the sight of blood
- high levels of anxiety
- standing up for long periods of time
- coughing, sneezing or laughing
- straining on the toilet
- heat exposure
How is fainting treated?
If you see someone faint, loosen any tight clothing and get them some fresh air.
If they are unconscious, follow DRSABCD.
|Letter||Representing||What to do|
|D||Danger||Ensure that the patient and everyone in the area is safe. Do not put yourself or others at risk. Remove the danger or the patient.|
|R||Response||Look for a response from the patient — loudly ask their name, squeeze their shoulder.|
|S||Send for help||If there is no response, phone triple zero (000) or ask another person to call. Do not leave the patient.|
|A||Airway||Check their mouth and throat is clear. Remove any obvious blockages in the mouth or nose, such as vomit, blood, food or loose teeth, then gently tilt their head back and lift their chin.|
|B||Breathing||Check if the person is breathing abnormally or not breathing at all after 10 seconds. If they are breathing normally, place them in the recovery position and stay with them.|
|C||CPR||If they are still not breathing normally, start CPR. Chest compressions are the most important part of CPR. Start chest compressions as soon as possible after calling for help.|
|D||Defibrillation||Attach an Automated External Defibrillator (AED) to the patient if one is available and there is someone else who is able to bring it. Do not get one yourself if that would mean leaving the patient alone.|
When they are conscious, lie them on their back and raise their legs, for example by putting a pillow underneath.
Putting their head between their knees and splashing water on their face won’t work.
Can fainting be prevented?
If you’re feeling faint, lie down with your legs raised slightly higher than your head. Be careful when moving and change positions very slowly, especially when moving from a lying or standing position
If you’re pregnant, avoid lying on your back, especially during the later months of pregnancy, because the pressure of your expanding uterus (womb) on your major blood vessels may cause you to feel faint.
Eating a healthy diet and not missing meals can help. Drink plenty of clear fluid, unless you have an existing medical condition which means this is not possible.
If you’ve fainted, you should avoid driving or operating any machinery until you have discussed your fainting with a healthcare professional.
In this Article
- Tips for Handling a Dizzy Spell
- When Should I Call a Doctor?
- What Are the Causes?
- Who Is More Likely To Get Dizzy?
DizzinessВ is a common problem and usually isnвЂ™t serious.В
During a spell of dizziness, you may feel as though youвЂ™re spinning or moving when youвЂ™re not (thatвЂ™s called vertigo). You may also feel:
- Lightheaded or faint
- Unsteady on your feet
- Woozy, as though your head is heavy or floating
Dizzy spells are different fromВ the sudden onset of dizziness, whichВ could be a sign of stroke. Go to the ER immediately.В
Tips for Handling a Dizzy Spell
If you feel dizzy, sit or lie down at once. This will lower your chance of falling down. If you have vertigo, it may help to lie down in a dark, quiet place with your eyes closed.
Drinking water may also give you fast relief, especially if youвЂ™re dizzy because youвЂ™re dehydrated.
If youвЂ™ve had a series of dizzy spells, there are things you can do to make yourself safer. Here are some of them:
- Remove tripping hazards in your home, such as rugs on the floor, so that youвЂ™re less likely to fall.
- Avoid alcohol, caffeine and tobacco, which can make symptoms worse.
- Drink enough fluids and get plenty of sleep.
- Be aware of things that trigger your dizziness, such as lights, noise, and fast movement, and try to be around them less or move more slowly.
When Should I Call a Doctor?
If youвЂ™ve had many bouts of dizziness or spells that last a long time, make an appointment with your doctor.
You should seek help immediatelyВ if youвЂ™re dizzy and also have:
- Chest pain or shortness of breath
- Severe headache
- Sudden change in your vision or hearing, or trouble speaking
- Numbness or weakness
- A head injury
- High fever
- Stiffness in your neck
What Are the Causes?
Keeping you upright and balanced is not an easy job for the brain. It needs input from several systems to do that.
Your doctor may ask you some questions to help narrow down the cause of your problem: What were you doing before your dizziness? What did you feel like during your spell? How long did it last?
Your dizziness might be the result of a circulatory problem. These can include:
- A sudden drop in blood pressure. This can happen after you sit up or stand too quickly. You might hear your doctor or nurse call this вЂњorthostatic hypotension.вЂќ
- Poor blood circulation. This could be the result of an irregular heartbeat or a heart attack. It could also be a brief disruption of the blood flow to your brain; thatвЂ™s called a вЂњtransient ischemic attack,” or stroke.
Issues with your inner ear can also cause dizziness. Among them are:
- MeniereвЂ™s syndrome. This usually affects only one ear. Symptoms other than dizziness may include ringing in your ear, muffled hearing, nausea or vomiting.
- Benign paroxysmal positional vertigo. This is a spinning sensation brought on by moving your head.
- Ear infection. That can cause dizziness. Also, you could have something trapped in your ear canal.
Some other causes of dizziness include:
- Medicines, such as antidepressants, anti-seizure drugs, tranquilizers and sedatives. If you take medication for high blood pressure, it might lower your blood pressure too much, leaving you feeling faint.
- Anxiety disorders. These include panic attacks.
- Low iron levels in your blood. This is also called anemia. Other signs that you are anemic include fatigue, pale skin and weakness.
- Low blood sugar. This is also called hypoglycemia. This may be a problem if you are diabetic and use insulin. Other symptoms include sweating and anxiety.
Who Is More Likely To Get Dizzy?
The older you are, the greater your chance for problems with dizziness. As you age, youвЂ™re also more likely to take medications that have it as a possible side effect.
If youвЂ™ve had a dizzy spell in the past, your odds of having a problem again are increased.
The most serious complication with dizziness is falling. It may also be unsafe for you to drive or perform other tasks. If your dizziness is caused by an underlying health problem, you may face other problems if that condition goes untreated.
National Health Service (U.K.): вЂњHealth A-Z вЂ“ Dizziness.вЂќ
Cleveland Clinic: вЂњDiseases and Conditions вЂ“ Dizziness.вЂќ
Mayo Clinic: вЂњDiseases and Conditions вЂ“ Dizziness.вЂќ
Vestibular Disorders Association: вЂњThe Human Balance System.вЂќ
National Stroke Association: вЂњTransient Ischemic Attack.вЂќ
American Speech-Language-Hearing Association: вЂњDizziness and Vertigo.вЂќ
Vestibular Disorders Association: вЂњCauses of Dizziness.вЂќ
Last Updated March 2021 | This article was created by familydoctor.org editorial staff and reviewed by Kyle Bradford Jones
Table of Contents
What is fainting?
Fainting happens when your brain does not get enough oxygen. You lose consciousness, or “pass out,” for a brief time (usually just a few seconds or minutes).
Symptoms of fainting
The primary symptom of fainting is losing consciousness. But there are other symptoms that may occur before you faint. These include feeling:
You also may have a headache or ringing in your ears.
What causes fainting?
Fainting, which is also called syncope, can be caused by many different things. Sometimes a specific cause for fainting cannot be found.
A sudden drop in your blood pressure can cause you to faint. Sometimes your heart rate and blood vessels can’t react fast enough when your body’s need for oxygen changes. This is very common among older people. It is also common in people who have certain health conditions, such as diabetes. Fainting can happen when:
- You stand up too fast
- You work or play hard (especially if it’s very hot)
- You begin to breathe too fast (called hyperventilating)
- You get very upset (being upset can affect the nerves that control your blood pressure)
- You’re taking medicine for high blood pressure
Coughing, urinating, and stretching can also get in the way of the flow of oxygen to the brain and may cause you to faint. If you faint once during one of these activities, it’s probably not something to worry about. But if it happens more than once, tell your doctor about it.
If you faint when you turn your head to the side, the bones in your neck may be pinching one of the blood vessels that lead to your brain. If this happens to you, be sure to tell your doctor about it.
A drop in your blood sugar may also cause you to faint. This can happen if you have diabetes. It may also happen if you don’t eat for a long time.
Some prescription medicines can cause fainting. Be sure to talk to your doctor if you think your fainting may be related to a medicine you’re taking.
Alcohol, cocaine, and marijuana can also cause fainting.
More serious causes of fainting include seizures and problems with the heart or with the blood vessels leading to the brain.
How is fainting diagnosed?
Your doctor will probably ask you about what was happening or what you were doing when you fainted. They may ask you for details about how you felt right before and right after you fainted. Your doctor will probably also want to examine you and may perform some tests to find out why you fainted.
Can fainting be prevented or avoided?
People who have certain medical conditions are more likely to faint. These conditions include:
- Heart problems (irregular heartbeat or blockages in or near the heart that prevent the blood from getting to the brain)
- Anxiety or panic disorders
- Low blood sugar
What should I do if I think I’m going to faint?
If you feel like you’re going to faint, lie down. If you can’t lie down, sit and bend forward with your head between your knees. This helps get the blood flowing to your brain. Wait until you feel better before trying to stand up. When you stand up, do so slowly.
You probably don’t need to go to your doctor if you have only fainted one time and you are otherwise in good health. Fainting is common and usually not serious. However, if you have serious health problems or are on multiple medications, you probably should see your doctor. This is especially important if you have heart-related problems, high blood pressure, or diabetes. See your doctor if you faint and also have any of these symptoms or conditions:
- Irregular heartbeat
- Chest pain
- Shortness of breath
- Sudden onset (no warning signs)
- Blurred vision
- Trouble talking
- Taking longer than a few seconds to regain consciousness
- Fainting when you turn your head to the side
- Fainting more than once in a month
Living with fainting
In most cases, fainting can be treated and controlled. Often, diagnosing what is causing fainting is the most difficult part. If your fainting is not under control, you should talk to your doctor about whether it is safe for you to drive.
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Fainting is a temporary loss of consciousness. If you’re about to faint, you’ll feel dizzy, lightheaded, or nauseous. Your field of vision may “white out” or “black out.” Your skin may be cold and clammy. You lose muscle control at the same time, and may fall down.
Fainting usually happens when your blood pressure drops suddenly, causing a decrease in blood flow to your brain. It is more common in older people. Some causes of fainting include:
- Heat or dehydration
- Emotional distress
- Standing up too quickly
- Certain medicines
- Drop in blood sugar
- Heart problems
When someone faints, make sure that the airway is clear and check for breathing. The person should stay lying down for 10-15 minutes. Most people recover completely. Fainting is usually nothing to worry about, but it can sometimes be a sign of a serious problem. If you faint, it’s important to see your health care provider and find out why it happened.
Dizziness is a word that’s often used to describe two different feelings. It’s important to know exactly what you mean when you say “I feel dizzy.” It can help you and your doctor narrow down the list of possible problems.
- Lightheadedness is a feeling that you are about to faint or “pass out.” You may feel dizzy. But you don’t feel as though you or your surroundings are moving. The feeling often goes away or improves when you lie down. If it gets worse, it can lead to a feeling of almost fainting or to a fainting spell ( syncope ). You may sometimes feel nauseated or vomit when you are lightheaded.
- Vertigo is a feeling that you or your surroundings are moving when there is no actual movement. You may feel as though you are off balance, spinning, whirling, falling, or tilting. When you have severe vertigo, you may feel very nauseated or vomit. You may have trouble walking or standing. And you may lose your balance and fall.
Dizziness can occur in people of any age. But it’s more common among older adults. A fear of dizziness can cause older adults to limit their physical and social activities. Dizziness can also lead to falls and other injuries.
It’s common to feel lightheaded from time to time. Brief bouts of lightheadedness aren’t usually caused by a serious problem. Lightheadedness often is caused by a quick drop in blood pressure and blood flow to your head. This can occur when you get up too quickly from a seated or lying position ( orthostatic hypotension ). Lightheadedness that lasts may mean that you have a more serious problem that needs to be checked.
Lightheadedness has many causes. They include:
- Illnesses such as the flu or colds. Home treatment of your flu and cold symptoms usually will relieve lightheadedness.
- Vomiting, diarrhea, fevers, and other illnesses that cause dehydration .
- Very deep or rapid breathing ( hyperventilation ).
- Anxiety and stress .
- The use of tobacco, alcohol, or illegal drugs.
A more serious cause is bleeding. Most of the time, the location of the bleeding and the need to seek medical care are clear. But sometimes bleeding isn’t obvious (occult bleeding). You may have small amounts of bleeding in your digestive tract over days or weeks without noticing the bleeding. When this happens, lightheadedness and fatigue may be the first signs that you are losing blood. Heavy menstrual bleeding also can cause this type of lightheadedness.
Sometimes the cause of lightheadedness is an abnormal heart rhythm ( arrhythmia ). This can cause fainting spells (syncope). Unexplained fainting spells need to be checked by a doctor. You can check your heart rate by taking your pulse .
Many prescription and nonprescription medicines can cause lightheadedness or vertigo. How bad it is depends on the medicine you take.
Vertigo occurs when there is conflict between the signals sent to the brain by the different systems of the body that sense balance and position. Your brain uses input from four sensory systems to maintain your sense of balance and orientation to your surroundings.
- Vision gives you information about your position and motion in relationship to the rest of the world. This is an important part of the balance mechanism. It often overrides information from the other balance-sensing systems.
- Sensory nerves in your joints allow your brain to keep track of the position of your legs, arms, and torso. Your body can then make tiny changes in posture that help you keep your balance (proprioception).
- Skin pressure sensation gives you information about your body’s position and motion in relationship to gravity.
- A portion of the inner ear, called the labyrinth, which includes the semicircular canals, contains specialized cells that detect motion and changes in position. Injury to or diseases of the inner ear can send false signals to the brain. They can tell the brain that the balance mechanism of the inner ear (labyrinth) detects motion. If these false signals conflict with signals from the other balance and positioning centers of the body, vertigo may occur.
Common causes of vertigo include:
- Inner ear disorders. Examples are benign paroxysmal positional vertigo (BPPV) , Ménière’s disease , vestibular neuritis , and labyrinthitis .
- Injury to the ear or head.
- Migraine headaches . They are painful, debilitating headaches that often occur with vertigo, nausea, vomiting, and sensitivity to light, noise, and smell.
- Decreased blood flow through the arteries that supply blood to the base of the brain (vertebrobasilar insufficiency).
Less common causes of vertigo include:
- A noncancerous growth in the space behind the eardrum (cholesteatoma).
- Brain tumors and cancer that has traveled from another part of the body (metastatic).
Medical care is needed right away if vertigo occurs suddenly with a change in speech or vision or other loss of function. Vertigo that occurs with loss of function in one area of the body can mean a problem in the brain, such as a stroke or a transient ischemic attack (TIA) .
Alcohol and many prescription and nonprescription medicines can cause lightheadedness or vertigo. These problems may develop from:
- Taking too much of a medicine (overmedicating).
- Alcohol and medicine interactions. This is a problem that often affects older adults, who may take many medicines at the same time.
- Misusing a medicine or alcohol use disorder.
- Drug intoxication or the effects of withdrawal.
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- When does dizziness generally start during pregnancy?
- Is dizziness a common early sign of pregnancy?
- What causes dizziness during pregnancy?
- What can I do about dizziness when I’m pregnant?
- Can I prevent dizziness during pregnancy?
- When does dizziness during pregnancy usually end?
- When should I call the doctor about dizziness during pregnancy?
Throughout your pregnancy, you may experience a disorienting feeling of unsteadiness, or vertigo, that can make you feel as if you’re about to fall or faint. But don’t worry, it’s a normal and fairly common symptom of pregnancy that you can, for the most part, avoid by taking a few smart steps.
When does dizziness generally start during pregnancy?
Many women experience dizziness starting between week 12 and the first few weeks of the second trimester of pregnancy.
Is dizziness a common early sign of pregnancy?
Dizziness is not usually one of the first signs of pregnancy, but it can be an early pregnancy symptom if you have low blood sugar due to a case of morning sickness. You may feel dizzy as a sign of pregnancy even before a missed period if you’re not eating much because you’re feeling nauseous, which can sometimes (but definitely not always) occur within days of conception.
What causes dizziness during pregnancy?
Early in pregnancy, your body is gearing up to meet the needs of two bodies instead of one. Dizziness is likely due to several factors:
- Your body isn’t yet producing enough blood to fill a rapidly expanding circulatory system.
- High levels of progesterone can also make your blood vessels relax and widen, increasing blood flow to your baby but slowing it down to you — which can reduce your blood pressure. This, in turn, cuts back on blood flow to your brain, sometimes making your head spin.
- Your growing uterus can put pressure on your blood vessels, especially when you’re lying on your back.
- It’s not called a bun in the oven for nothing: Your body is generating plenty of heat right now, which means spending too much time in a hot or stuffy room can contribute to feelings of lightheadedness.
- If your blood sugar drops or you become dehydrated, you’re more likely to experience a dizzy spell.
What can I do about dizziness when I’m pregnant?
Keep in mind that no matter how “normal” dizziness is, you shouldn’t ignore it. So use common sense: no driving, working out or handling anything that could potentially cause you harm. If you need help, don’t be shy about asking.
Read This Next
To stop a dizzy spell, lie down as soon as you start to feel lightheaded so you don’t fall or pass out, then elevate your feet to increase blood flow to your brain.
If that’s not possible, sit down and bend as far forward as you’re able to, putting your head between your knees if you can, and breathe slowly and deeply. If there’s no place to lie down or sit, kneel on one knee and bend forward as if you were tying your shoe until the spell passes.
Can I prevent dizziness during pregnancy?
To keep dizziness from starting in the first place:
- Go slowly. Don’t get up too quickly when you’re sitting or lying down, since it can cause your blood pressure to drop, triggering dizziness.
- Make the most of the munchies. Make sure you’re eating a healthy, well-rounded diet during pregnancy, with a mix of protein and complex carbs (like whole grain bread or pasta) at every meal to maintain stable blood sugar levels.
- Feast frequently. Chow down on several small meals throughout the day to prevent dips in your blood sugar, and carry healthy pregnancy snacks with you for a quick blood sugar boost. Good options: a mini-box of raisins, a piece of fruit or some whole wheat crackers.
- Fill up on fluids. Make sure you’re drinking enough water, since dizziness can be a sign of dehydration, too. Aim for around 12 to 13 glasses of fluids a day, and more if it’s hot or you’re working out.
- Dress smart. Wear easy-to-shed layers in case you start feeling overheated, and avoid wearing tight-fitting clothes, scarves or hats.
- Don’t lie on your back. In your second and third trimesters, it’s best to avoid sleeping on your back, as your growing uterus can press on the vena cava (the main vein that carries blood back to the heart from your lower body region). That can interfere with optimum circulation and cause a feeling of dizziness.
- Get some fresh air. Spending too much time in a stuffy, overheated indoor space (like a crammed bus, office or store) can trigger dizziness, so as long as you’re not feeling overly faint, try to take a five-minute walk outside every hour or so — which can help relieve other pregnancy symptoms like constipation and swelling, too.
When does dizziness during pregnancy usually end?
Once they start, dizzy spells can often last through the rest of your pregnancy. But they should subside after your baby is born.
When should I call the doctor about dizziness during pregnancy?
Sometimes iron deficiency (anemia) can result in fainting spells as oxygen-carrying blood cells are depleted. So if you actually pass out, call your doctor ASAP.
Some women might wonder whether dizziness is a symptom of miscarriage. Not to worry: Lightheadedness is not a common sign of miscarriage.
Others may have questions about whether dizziness might be a symptom of preeclampsia. But there’s no reason to be concerned there, either. Feeling faint is not a common sign of preeclampsia, which is characterized by the sudden onset of high blood pressure during pregnancy, while dizziness is often caused by the opposite problem: low blood pressure.
The bottom line is that if dizziness or lightheadedness are persistent even after you take steps to treat and prevent them, tell your practitioner how you’re feeling at your next visit.
From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You’re Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.
The sight of blood. Crossing paths with a famous person. Anxiety on your wedding day. These are typical scenarios in movies, or even real life, where the outcome is someone fainting. But what exactly is going on in our body that causes us to lose consciousness?
Fainting, also known as syncope, occurs when the brain does not get enough oxygen. Low oxygen to the brain can be due to a sudden drop in blood pressure. The nervous system signals the heart to slow down and blood vessels to widen, leading to low blood pressure. This sudden drop in pressure can be triggered by emotional or physical stress, such as a panic attack; working in extremely hot weather; or strenuous coughing.
Additionally, moving from a lying down position to sitting or standing up can cause blood pressure to drop. When fainting occurs in this situation, it is usually due to dehydration, taking certain medications or illegal drugs, or heavy blood loss.
Symptoms and risk factors
A person may start to feel weak, nauseous, sweaty, lightheaded or dizzy before actually losing consciousness. Certain medical conditions can also put someone at higher risk for fainting, including:
- Abnormal heart rhythm
- Diabetes (due to low blood sugar)
Fainting is usually not serious; if you are in overall good health, you may not need to see a doctor. However, if you have serious health issues or take medications, speak with your doctor if you’ve fainted, as well as to discuss your risks for fainting.
Also, let your doctor know if you have experienced these additional symptoms with fainting:
- Blurry vision
- Chest pain
- Irregular heartbeat
- Shortness of breath
- Trouble talking
- Unconsciousness for more than a few seconds
- Fainting when you turn your head to the side
- Fainting more than once in a month
10 tips to avoid fainting
There are ways to prevent fainting, as well as ways to help someone who has fainted. Dr. Hans Crumpler, a family medicine doctor with SharpCare Medical Group and affiliated with Sharp Grossmont Hospital, shares these 10 tips:
- If you can do so safely, lie down and elevate your legs to just above hip level. This helps regulate blood flow and get circulation to the brain and vital organs.
- If you cannot lie down safely, try to sit down, bringing your head as close as possible to your knees. This helps redistribute blood flow to the brain. Also, there is less distance to fall, and you may potentially avoid head trauma in case you do fall.
- If you do sit or lay down, do not try to get up rapidly. Wait until your feeling of lightheadedness improves and then stand up slowly to avoid restarting symptoms.
- Try to tense up your arm muscles and make fists, which can help with blood flow in the upper body. Brace yourself to avoid hitting the ground with force if you do pass out.
- Crossing your legs or pressing them together also helps to increase blood circulation in the upper body. If standing for long periods of time, do not lock your knees because this can restrict circulation and lead to fainting.
- Avoid long periods of time without food. Eating consistently not only helps maintain your caloric needs but it also regulates blood sugar levels. Low blood sugar can cause fainting.
- Slowly drinking sips of water or electrolyte solution can help avoid passing out due to dehydration.
- Taking slow, deep breaths helps avoid fainting because it increases oxygen and blood flow in the body.
- If you see someone passing out near you, try to get them to the floor or sit them up carefully to avoid traumatic injury. Protect them from hitting objects as they come down and help them consume food or water if they respond appropriately.
- If you assist someone who has passed out, keep them still as best as you can to avoid further injury. Monitor their breathing, check for obvious injuries, and call for medical help so that the person can get a full evaluation.
What is syncope?
Syncope (SINK-a-pee) is another word for fainting or passing out. Someone is considered to have syncope if they become unconscious and go limp, then soon recover. For most people, syncope occurs once in a great while, if ever, and is not a sign of serious illness. However in others, syncope can be the first and only warning sign prior to an episode of sudden cardiac death. Syncope can also lead to serious injury. Talk to your physician if syncope happens more often.
Pre-syncope is the feeling that you are about to faint. Someone with pre-syncope may be lightheaded (dizzy) or nauseated, have a visual “gray out” or trouble hearing, have palpitations, or feel weak or suddenly sweaty. When discussing syncope with your doctor, you should note episodes of pre-syncope as well.
Becoming unconscious due to a seizure, heart attack, head injury, stroke, intoxication, blow to the head, diabetic hypoglycemia or other emergency condition is not considered syncope.
Someone who faints should be moved so they are lying down to allow blood to flow to the brain. If they do not regain consciousness promptly, start CPR.
What causes syncope?
Syncope occurs when there is not enough blood flow to the brain. There are many potential causes, but the most common ones include:
Serious Cardiovascular Conditions (Cardiac Syncope)
If fainting occurs frequently and is not because of dehydration or sudden postural change, you may need to be tested for a serious heart or vascular condition. Cardiac syncope often occurs suddenly, without dizziness or other pre-syncope symptoms.
Common causes of cardiac syncope:
Arrhythmia and abnormal heart rhythm: During episodes of heart arrhythmia, the heart works inefficiently and not enough oxygenated blood can circulate to the brain. There are many types of cardiac arrhythmias that may cause syncope. These include bradyarrhythmias (the heart beats too slowly) and tachyarrhythmias (the heart beats too fast).
Aortic dissection, a tear in the large artery that carries blood from the heart to the rest of the body. This is a very rare but life-threatening condition.
Aortic valve stenosis, a narrowing of the valve between the heart and the aorta. Aortic valve stenosis can be congenital (present from birth) or can develop in old age.
Reflex Syncope (Neurally Mediated Syncope, Vasovagal Syncope, Vasodepressor Syncope, the Common Faint)
Reflex syncope is the result of a reflex response to some trigger, in which the heart slows or blood vessels dilate (widen). This causes blood pressure to drop, so less blood flows to the brain and fainting (syncope) or near-fainting (pre-syncope) occurs. Reflex syncope is the most frequent cause of fainting.
Vasovagal syncope — the common faint — occurs in one third of the population. It is by far the most common form of reflex syncope. Vasovagal syncope is often triggered by a combination of dehydration and upright posture. But it can also have an emotional trigger such as seeing blood (“fainting at the sight of blood”).
Some Vasovagal Syncope Triggers
Seeing blood (not considered a serious symptom)
Getting an injection or having blood drawn (not considered serious)
Standing up quickly (a “head rush” is considered pre-syncope)
Standing upright for a long time
Sudden and unexpected trauma, stress or pain, such as being hit
Other types of reflex syncope include:
Situational syncope, a sudden reflex response to a trigger other than those listed above. Triggers include:
Coughing, sneezing, laughing, swallowing
Pressure on the chest after exertion or exercise
Urinating (post-micturition syncope: occurs in men while standing to urinate)
Sudden abdominal pain
Blowing a brass instrument or lifting weights
Carotid Sinus Syncope, a response in older adults that occurs when pressure is applied to the carotid artery in the neck. A hard twist of the neck, wearing a tight collar and pressing on the artery are triggers for carotid sinus syncope.
Orthostatic (upright) hypotension (low blood pressure when standing) can also cause fainting because blood has trouble going against gravity to reach the brain. Orthostatic hypotension is defined as a fall in systolic blood pressure of 20 mmg Hg or more on standing, resulting in syncope or pre-syncope. Orthostatic hypotension is common in elderly individuals and is often exacerbated by dehydration or medications that lower blood pressure, such as diuretics. Less commonly, orthostatic hypotension can be caused by a neurologic condition such as Parkinson’s disease or multisystem atrophy, formerly known as Shy-Drager syndrome.
Postural Orthostatic Tachycardia Syndrome (POTS)
Postural orthostatic tachycardia syndrome (increased heart rate when standing), or POTS, is a rare clinical syndrome characterized by an increase in heart rate of at least 30 beats per minute on standing and orthostatic intolerance — when standing brings on symptoms such as palpitations, lightheadedness and fatigue. POTS generally appears in young women. After excluding other causes, the diagnosis is made on physical examination, medical history and tilt-table test. Treatment usually consists of increased salt and fluid intake, recumbent exercise (not standing upright) and education in avoiding triggers. POTS does not usually get worse with age.
How is syncope diagnosed?
It’s important to identify the cause of syncope, if possible, to rule out a dangerous heart condition. Depending on your symptoms and circumstances, the following tests may be used to find the cause:
On-site Diagnostic Tests
Electrocardiogram (ECG or EKG): wires taped to various parts of your body to create a graph of your heart’s electrical rhythm
Exercise stress test: ECG recorded while strenuously exercising
Physical examination, including orthostatic vital signs and carotid sinus massage
Tilt table test: measurement of heart rate and blood pressure in response to upright tilt, which simulates prolonged standing
Electrophysiology study (EP): test that examines the heart’s electrical activity from the inside; used to diagnose many heart rhythm disorders
In-home Diagnostic Monitors
Holter monitor: a portable ECG you wear continuously for one to seven days to record your heart rhythms over time
Event monitor: a portable ECG you wear for one or two months, which records only when triggered by an abnormal heart rhythm or when you manually activate it
How is syncope treated?
The treatment for syncope will depend upon the underlying condition but may include:
Catheter ablation: procedure to cauterize the specific heart cells that cause abnormal heart rhythms
Pacemakers: device inserted under the skin below the collarbone to deliver regular electrical pulses through thin, highly durable wires attached to the heart; used to treat bradycardia, heart block and some types of heart failure
Implantable cardioverter-defibrillators (ICDs): a small implanted device that delivers an electrical pulse to the heart to reset a dangerously irregular heartbeat; often used to treat ventricular tachycardia or heart failure