Just in case you’ve never seen anyone – in real life, or on-screen – faint, this is when someone suddenly passes out, and, if they’re standing, falls down.
This can be quite alarming, but they will usually come to in a short time, often no more than a minute or two. Make sure that the person who has fainted is breathing, that their colour is returning to normal, and they aren’t choking.
However, if the person who has fainted doesn’t start showing signs of recovery and consciousness within two minutes, don’t wait. Call an ambulance straight away.
About 50% of the population experience syncope - see below for the definition - so it’s important to know the causes, symptoms, and what to do if someone faints.
What is a syncopal episode?
The medical term for fainting caused by a sudden drop in blood supply – and oxygen - to your brain is syncope. This is pronounced sin-co-pee. There are different types of syncope, but these are some of the most common. Reflex syncope is when your autonomic nervous system (which controls your heart rate and blood pressure), has a temporary glitch. When this happens, the nerves that control the width of your blood vessels and keep your blood pressure level stop working briefly. The result is that your blood pressure falls. This can then mean that your vagus nerve, which controls your heart rate, causes your heart rate to drop. This condition is called bradycardia.
The result is that your blood pressure or your heart rate, or both, can drop dramatically. As a result your brain and other organs suddenly stop getting their normal amount of blood, oxygen and other important elements.
Common triggers for a dizzy spell
When this happens it can make you feel very dizzy, and have the blackouts we know as fainting. There are known triggers - emotional stress, pain, being in a frightening or unpleasant situation, being too hot, and the sight of blood can all cause fainting.
Other types of fainting include situational syncope. This can happen when normal daily situations, such as laughing, coughing or sneezing, cause sudden extra demands on your autonomic nervous system.
Postural tachycardia syndrome
Even standing up or sitting up straight can make you faint, or leave you feeling dizzy and rather sick. This is known as postural tachycardia syndrome (PoTS).
Normally when you stand or sit up some of your blood goes down to the lower parts of your body. To keep enough blood reaching your heart and brain, your body reacts, constricting your blood vessels, and pushing your heart rate up slightly – reactions that happen automatically, and you won’t notice.
If you have PoTS, this reaction doesn’t happen, and the reduction in the amount of blood reaching your heart and brain can make you faint.
Your body has an automatic way of correcting this situation. Your heart starts beating more rapidly, and your body sends out a stress hormone – noradrenalin - that also speeds up your heart rate, and increases your blood pressure.
You’re more likely to faint when you stand up, because this can cause a drop in your blood pressure. It can also be a result of standing for a long time, especially in the heat. This is orthostatic hypotension and is especially common in people aged 65 and over.
Symptoms of fainting
If you faint often, make a note of the symptoms you have each time this happens. They may include feeling dizzy, light headed and nauseous, hot and sweaty, and having palpitations and blurred vision and feeling generally weak. People about to faint can become very pale.
Underlying conditions that can cause fainting
Fainting can be caused by something as simple as dehydration. However it can also be caused by a number of underlying medical conditions, which is why it is important to see your GP. The medical conditions that can cause fainting include:
- Low blood pressure
- Uncontrolled diabetes
- Neurological conditions, such as Parkinson’s disease
- Heart conditions, including angina, problems with your heart muscles
- Strokes and transient ischaemic attacks (mini-strokes)
- Low blood sugar
Medication that you are taking for existing health conditions may also cause fainting.
Medical diagnosis of fainting
If you faint often, or it has reached the stage where it is affecting your life and well being, you need medical advice treatment to help you cope with it, and the underlying causes.
This is why diagnosis is important. See your GP, and take with you a diary of the dates on which you fainted, and include details on what you had been doing – and feeling – immediately before you fainted, what symptoms you had before you passed out.
Remember to also keep a record what you had been eating and drinking, and what medication you had been taking – both prescribed and over the counter. This information can help your doctor find out what is behind the fainting.
They will also be able to decide whether you have an undiagnosed medical problem that needs further medical investigation and treatment, and whether you need to change the medication you’re taking for an existing problem.