Why dreamers are less likely to suffer a stroke
THEY often make little sense and can be annoyingly hard to remember in the morning. But regular dreams could slash your risk of a stroke, research suggests.
Those who enjoy so-called dream phase sleep every night are much less likely to suffer a dangerous heart condition that doubles the risk of a potentially life-threatening stroke.
Tests showed volunteers who spent several hours a night in the REM – or rapid eye movement – stage of sleep had much lower rates of atrial fibrillation, an irregular heart beat that affects at least two million people in Britain and can cause blood to pool in the chambers of the heart.
Those who woke frequently were 36 per cent more likely to develop it, scientists at the University of California San Francisco found.
Atrial fibrillation is a major cause of strokes. Tiny bits of clotted blood can break away and get stuck in the narrow vessels around the brain, starving it of oxygen.
The cause is unknown, though high blood pressure, chest infections and an overactive thyroid are possible triggers.
The Arrhythmia Alliance claims it causes around 16,000 strokes a year in the UK and fears up to half-a-million people may not even realise they have it as they suffer no obvious symptoms.
While some sufferers feel heart palpitations and get breathless, others have no idea they are ill. It develops when electrical activity in the heart goes haywire and causes the heart to beat irregularly.
As the heart no longer beats in a regular fashion, blood which should be pumped round the body instead begins to collect and thicken inside the left ventricle, the heart’s main pumping chamber.
If a clot breaks away and travels up through the narrow blood vessels that feed the brain, it can cause a fatal stroke by blocking the supply of oxygen-rich blood.
Common treatments for atrial fibrillation include the blood-thinner warfarin to stop clots forming and cardioversion, where the heart is shocked back into normal rhythm using electrodes.
But experts now think getting a good night’s sleep could keep it at bay. Scientists tracked 5,703 adults over an 11-year period, many of whom took a sleep test to measure how many times a night they woke or stirred in their sleep. The results were then matched up with how many went on to develop atrial fibrillation.
The results, in the journal Heart-Rhythm, revealed that frequent stirrers were at least a third more likely to have abnormal heart rates than deep sleepers.
REM sleep makes up about a quarter of the rest the body gets every night – roughly two hours. While the eyes are busy twitching, muscles in the rest of the body are paralysed, to stop us acting out our dreams.
Scientists think one explanation for the health benefits of dream sleep is that it has a protective effect on the autonomic nervous system, which helps control heart rate and blood pressure.
Heart expert Dr Gregory Marcus, who led the research, called for larger studies to confirm the findings. He said: ‘Trials are needed to assess whether improving sleep quality can reduce the incidence of atrial fibrillation as well as recurrence among those who already have the disease.’