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Why fainting should never be dismissed as a funny turn 

Standing outside a bar after watching a film at a local cinema, Sarah Parmenter took a sip of her drink — and suddenly blacked out.

‘The next thing I knew I found myself slumped on the pavement with the friend I was with anxiously standing over me,’ recalls Sarah, 48. ‘Apparently I had passed out for about a minute.’

An off-duty nurse came over and helped her up. ‘I felt a bit light-headed, but I just thought it was one of those things,’ says Sarah.

Swooning? Every year, more than 200,000 people are hospitalised after suddenly fainting 

‘As a teenager, I used to faint occasionally, maybe a few times a year. My GP put it down to hormones, but it hadn’t happened to me for nearly 30 years. So I went straight home to bed, intending to sleep it off.’

However, a few weeks later, when Sarah travelled from her Manchester home to London for a break with friends, she found herself feeling faint again. This time her light-headedness was accompanied by sharp pains in her ribs and chest.

‘I was at the hotel and thought maybe I’d pulled a muscle in my stomach,’ she says. ‘But the pain got worse and I felt really light-headed. I went to reception to ask about seeing a doctor and they took one look at me and said I should get a taxi straight to A&E. Clearly, I must have looked awful.’

Once in hospital, an X-ray revealed a potentially serious cause of Sarah’s faints. She had several blood clots on her lungs, a condition known as pulmonary embolism.

‘I was horrified to learn untreated lung clots can be fatal,’ recalls Sarah, a divorced mother of two who restores furniture. ‘I couldn’t understand why it had happened. I was slim and otherwise healthy. In a way I was lucky to have the faints — they were a warning sign.’

Every year, more than 200,000 people are hospitalised after a sudden blackout.

Recently, Simon Cowell missed the first live show of this year’s X Factor after fainting and falling on the stairs of his home.

He reportedly put this down to the fact he has low blood pressure — without sufficient blood flow, not enough oxygen reaches the brain stem, which is responsible for consciousness and keeping us awake.

Blackout: Simon Cowell recently revealed that his low blood pressure caused him to faint

Blackout: Simon Cowell recently revealed that his low blood pressure caused him to faint

However, there are many other causes of fainting — some quite innocent, and some, as Sarah discovered, far more sinister.

The vast majority of cases are caused by what’s known as a vasovagal attack, explains Professor Charles Knight, a consultant cardiologist at Barts Health NHS Trust, London.

‘This is when the vagus nerve, which runs from the brain to the abdomen and which controls the heart rate and blood pressure, becomes overactive, causing heart rate to drop and this leads to a sudden drop in blood pressure,’ he says. ‘Usually there is a trigger, such as being hot or dehydrated. In these situations, fainting is usually preceded by a feeling of nausea, sickness or just feeling unwell.’

People can faint from hunger due to a drop in blood sugar because lack of food means the brain doesn’t get enough glucose.

But fainting can be a sign of something serious. In fact, faints caused by a blood clot in the lung — as happened to Sarah — occur more frequently than many doctors suspect, according to an Italian study published last year in the New England Journal of Medicine.

Clots in the lung were found in around 17 per cent of the 560 patients who had been taken to hospital after fainting.

Dr Keith Prowse, a consultant chest physician and spokesman for the British Lung Foundation, says clots in the lungs can happen at any time, and may be triggered by periods of immobility brought on by, say, a long-haul flight. The inactivity causes blood to pool, which encourages the formation of clots in the legs that can then travel to the lungs.

‘If lung capacity is diminished by the clot and there is a disruption to circulation because of the clot then blood pressure drops leading to fainting,’ explains Dr Prowse. ‘That’s why doctors looking at patients with fainting spells should consider blood clots.’

Cardiac problems, such as arrhythmia, where the heart beats too slow or too fast, can also interrupt blood flow to the brain and lead to a temporary loss of consciousness, known as syncope, adds Professor Knight.

And around a third of ‘falls’ in the elderly are probably a blackout, according to Dr Adam Fitzpatrick, a consultant cardiologist and electrophysiologist at Manchester Royal Infirmary. However, some may end up in orthopaedics because of the injury caused by the collapse, while the reason for the fall isn’t investigated.

‘In elderly people, fainting is increasingly common and the underlying cause is often a side-effect of medication such as blood pressure tablets,’ adds Dr Adam Simon, a private GP based in Manchester.

‘The other problem is that older people become what’s known as deconditioned in terms of fitness level — that is, their strength in the upper legs drops and that can lead to a faint and a fall.’


■ Coughing. Research published in Respiratory Medicine stated that several hundred cases of fainting occurred as a result of coughing. It is believed to have been caused by sudden changes in blood pressure around the lung, diverting it away from the brain.

■ A trip to the loo. Micturition syncope is the medical term for fainting during urination. Some experts believe it is down to speedy relief given to the bladder which opens blood vessels up and lowers blood pressure.

A large bowel movement can also cause the vagus nerve, which runs from the brain to the abdomen, to become overstimulated. This directs blood from the brain, risking unconsciousness.

■ Laughing. In 2008, an obese man was reported to faint when he laughed. But experts say this, caused by the airways being closed off, is rare.

Another reason for fainting, particularly in the under-35s, may be a condition known as orthostatic intolerance.

It is caused by a malfunction of the autonomic nervous system — which controls unconscious activity such as heart rate. Normally when you stand up, your heart should beat faster and your blood vessels should narrow automatically to ensure adequate blood pumps not just to the legs, but also up to the brain.

However, in cases of orthostatic intolerance, this doesn’t happen, so there is a delay in adequate blood supply to the brain and those affected feel faint.

It is four times more common in women than men and may have a hormonal link, since it appears to be worse around the time of the menopause or a woman’s period.

This is sometimes misdiagnosed as chronic fatigue syndrome, according to Julia Newton, a clinical professor of ageing and medicine at the Newcastle upon Tyne Hospitals NHS Trust.

Possible triggers for orthostatic intolerance include viruses or recent surgery. ‘Dehydration can be an underlying cause as this depletes the volume of blood in the body,’ says Professor Newton.

‘And many people do get dehydrated after being ill or having surgery, but sometimes a virus can affect the autonomic nervous system, triggering the condition.’

Counter-manoeuvres will help. Professor Newton advises squeezing the bottom and legs for a few seconds before standing up and rocking back and forward on the heels as this will encourage blood flow back to the heart.

But regular fainting should be taken seriously, adds Professor Knight: ‘Most of the time there will be a simple trigger, such as overheating. But you need to seek medical attention to rule out anything more serious.’

Had Sarah ignored her fainting episodes five years ago, the result could have been far more serious. She was kept in hospital for five days while doctors showed her how to inject herself with the medication rivaroxaban to prevent further clots.

‘I’m so grateful the clots were diagnosed,’ Sarah says. ‘I realise now that if untreated, I could have died. I would urge anyone who faints to get checked out by a doctor.’