A faulty boiler. A trip to the pool. Even cat fur… What's behind your dizzy spells
00:15 GMT, 12 June 2012
Most of us have felt dizzy at some point, but can usually put it down to something harmless.
It might be from standing up too quickly — causing a momentary lack of blood and oxygen flowing through the head — or low blood sugar, where the brain doesn’t have enough fuel.
It’s estimated that a third of adults suffer from severe dizziness at some stage and there are many reasons for it, from the side-effects of certain medications, to heart conditions and even hay fever.
Here, DAVID HURST investigates some of the most common causes of those funny turns.
Dizziness might be caused from standing up too quickly – causing a momentary lack of blood and oxygen flowing through the head
Tablets used to treat high blood pressure, known as ACE inhibitors, can cause dizziness while your doctor is working out which dosage is appropriate for you — as can antidepressants such as amitriptyline.
Both drugs lower blood pressure which in turn trigger feelings of light-headedness.
‘And for some people taking a diuretic medicine (such as furosemide and bumetanide) for a heart condition can sometimes result in dehydration and may lead to dizziness,’ adds Natasha Stewart, senior cardiac nurse at the British Heart Foundation.
‘Therefore it’s important to get the right type and dose to suit your needs.’
Dehydration occurs as the diuretics cause the kidneys to get rid of extra water and salt.
Sedatives are another common culprit; they work by depressing the central nervous system, which in turn slows down brain activity.
Meanwhile, decongestants for a blocked nose work by narrowing blood vessels, which can affect how much oxygen reaches the brain.
Tiredness is the main symptom of anaemia, which occurs when the number of red blood cells is reduced because the body doesn’t have enough iron to produce them.
But the condition can also be characterised by vertigo-like feelings.
This is because red blood cells carry oxygen around the body in a substance called haemoglobin, so anaemia means insufficient oxygen may reach the brain.
Migraine sufferers appear to experience dizziness more often than non-sufferers
Migraine sufferers appear to experience dizziness more often than non-sufferers, says Susan Haydon, of the Migraine Trust.
‘It sometimes occurs as part of the “aura” — or warning signs — that many people with migraine have before their headache develops.
‘These may include visual problems such as flashing lights and stiffness in the neck, shoulders or limbs. Each dizzy spell can last from a few hours to several days.
‘Migraines may be caused by blood vessels narrowing in the brain, which may cause the dizziness by reducing blood flow to the area.’
The powerful magnetic fields that create detailed images of our insides during a magnetic resonance imaging (MRI) scan can also cause dizziness.
Our balance system is controlled by the inner ear, which comprises a system of narrow fluid-filled tubes called the labyrinth. When we move our head, the fluid in the labyrinth moves, too.
This sends messages to the brain, informing it about the movements and position of the head. You feel dizzy when the right and left balance systems do not work in symmetry and the brain thinks the head is moving when it’s not.
Now researchers from Johns Hopkins University in the U.S. have found the strong magnetic field in MRI scans push on fluid within the labyrinth, causing a feeling of dizziness.
If you’re feeling dizzy, it can be worth drinking a big glass of water to see if it helps.
The brain is mostly made of water, so dehydration means it doesn’t function as well.
Even a 1.5 per cent loss in normal water volume can alter our mood, energy level and ability to think clearly, according to research from the University of Connecticut.
Women are particularly sensitive to the adverse effects of dehydration.
‘Women’s blood is thicker, their body temperature is higher and their heart rate is faster, which might be why they are more sensitive to dehydration than men,’ suggests Professor Lawrence Armstrong, a nutritionist and physiologist from the university.
HEART AND BLOOD CONDITIONS
Many attacks of dizziness are caused by brief drops in blood pressure, leading to a fleeting reduction in the blood — and oxygen — supply to the brain.
This typically happens when getting up suddenly from a sitting or lying position, known as postural hypotension.
However, an arrhythmia — an abnormal heart rhythm — can also disrupt the blood supply to the brain, as can a heart rate that’s too fast or too slow.
In mini strokes (which affect around 50,000 Britons a year), a blood clot passes through the brain (in a full stroke there is a complete blockage) and can cause dizziness due to the temporary slowing down in the circulation of blood and oxygen.
Water inside the ears is a fact of life for swimmers. But if it interferes with the finely balanced workings of the inner ear, dizziness can last for hours or days until the water has drained out.
Wearing earplugs during a swim will help prevent this. And according to the American Academy of Otolaryngology (ear, nose and throat), feeling tense before or during swimmimg can reduce the blood circulation to your brain, resulting in dizziness.
Certain allergies, including those to peanuts, cats, dust and grass pollen, can make us feel rather wobbly
Certain allergies, including those to peanuts, cats, dust and grass pollen, can make us feel rather wobbly.
‘If you have a hay fever with sinus and middle ear congestion, then you probably would feel dizzy,’ says Dr Adrian Morris, principal allergist at the Surrey Allergy Clinic, Guildford.
‘In this case, the allergy has lead to mucus production in the sinuses and middle ear; they are now blocked and this affects balance and can cause dizziness.’
Around 40,000 people in the UK suffer from Meniere’s disease, which causes attacks of dizziness lasting anything from several minutes to 24 hours.
‘It can take months, or years, to diagnose this awful condition as doctors can’t see into the inner ear to determine whether it is Meniere’s or not,’ says Sarah Lucas of the Meniere’s Society.
‘It can be a very scary condition.’
The cause is not yet known, although it is possibly caused by a problem with pressure in the inner ear caused by fluid build-up.
Bone abnormalities in the middle ear and infections may also play a part. There is no established cure.
Another condition that can make you feel dizzy — BPPV, or Benign Paroxysmal Positional Vertigo, is thought to be caused by small fragments of debris that, for unknown reasons, break off from the lining of the inner ear and brush against the sensitive hairs, sending confusing messages to the brain.
Poorly-maintained heating appliances such as boilers can produce dangerous amounts of this gas, which can also build up to dangerous levels when flues, chimneys or vents are blocked.
Carbon monoxide prevents the bloodstream from absorbing oxygen.
Early symptoms of carbon monoxide poisoning are related to the fact that the brain can’t function correctly — dizziness is one of the first signs, as well as headache, fatigue, nausea and chest pains.
A study by University College London in 2007 found a fifth of all homes in the UK had at least one gas appliance rated as ‘at risk’ or ‘immediately dangerous’, leaving residents open to the possibility of breathing in carbon monoxide.