Moving clocks forward an hour may be dangerous for millions of people with heart problems 

For most of us it signals the end of the bleak winter months and the promise of longer days to come. 

But moving the clocks forward an hour tonight could be bad for the health of more than a million people in Britain with a lifethreatening heart problem. 

A major study shows losing an hour’s sleep due to daylight saving increases hospital admissions for a serious heart rhythm condition known as atrial fibrillation. 

It causes an estimated 16,000 strokes a year. Now scientists fear that the one-hour loss of sleep is enough to leave some sufferers needing emergency treatment because the effect on their circadian rhythm – or body clock – makes their heart rate go haywire. 

The study, by experts at the Albert Einstein College of Medicine in New York, backs up previous research suggesting heart attacks spike in the days after the clocks going forward. 

But moving them back an hour in the autumn does not appear to have the same effect, the scientists reported.

Moving the clocks forward an hour tonight could be bad for the health of more than a million people in Britain with a lifethreatening heart problem [File photo]

Atrial fibrillation develops when electrical activity in the heart goes haywire, causing it to beat irregularly. 

Symptoms include chest pain, dizziness and fatigue, but a significant number of sufferers have no idea they are ill until they have a stroke. 

Blood that should be pumped around the body begins to pool and thicken in the left ventricle. 

If a clot breaks away and travels up arrow blood vessels that feed the brain, it can block the supply of oxygen-rich blood, causing a stroke. 

The US team tracked 6,000 patients in their 60s over a sevenyear period. All the volunteers had atrial fibrillation that was treated with prescription medicines. 

The results, published in the journal Sleep Medicine, found hospital admissions with heart rhythm complications jumped around 25 per cent in the days following the clocks changing. 

Women were more affected than men. 

In a report on the findings, scientists said: ‘Daylight saving results in changes in circadian rhythms and disturbances in sleep duration that may last for weeks. This can affect heart rate and blood pressure.’ 

Last year the European Parliament voted to abandon daylight saving time – introduced during the First World War to save energy by prolonging daylight in summer.

The ruling is due to take effect next year but Britain has so far rejected the idea.  

The study, by experts at the Albert Einstein College of Medicine in New York, backs up previous research suggesting heart attacks spike in the days after the clocks going forward [File photo]